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# std.string

String handling functions.

Category | Functions
--- | ---
Searching | column indexOf indexOfAny indexOfNeither lastIndexOf lastIndexOfAny lastIndexOfNeither
Comparison | isNumeric
Mutation | capitalize
Pruning and Filling | center chomp chompPrefix chop detabber detab entab entabber leftJustify outdent rightJustify strip stripLeft stripRight wrap
Substitution | abbrev soundex soundexer succ tr translate
Miscellaneous | assumeUTF fromStringz lineSplitter representation splitLines toStringz

Objects of types `string`, wstring, and dstring are value types and cannot be mutated element-by-element. For using mutation during building strings, use char[], wchar[], or dchar[]. The xxxstring types are preferable because they don't exhibit undesired aliasing, thus making code more robust.
The following functions are publicly imported:

Module | Functions
--- | ---
Publicly imported functions
std.algorithm | cmp count endsWith startsWith
std.array | join replace replaceInPlace split empty
std.format | format sformat
std.uni | icmp toLower toLowerInPlace toUpper toUpperInPlace

There is a rich set of functions for string handling defined in other modules. Functions related to Unicode and ASCII are found in std.uni and std.ascii, respectively. Other functions that have a wider generality than just strings can be found in std.algorithm and std.range.
See Also:

- std.algorithm and std.range for generic range algorithms
- std.ascii for functions that work with ASCII strings
- std.uni for functions that work with unicode strings

License:
Boost License 1.0.
Authors:
Walter Bright, Andrei Alexandrescu, Jonathan M Davis, and David L. 'SpottedTiger' Davis

Source std/string.d

class `StringException`: object.Exception;
  Exception thrown on errors in std.string functions.
  Examples:

      import std.exception : assertThrown;
      auto bad = "      a\n\tb\n   c";
      assertThrown!StringException(bad.outdent);

pure nothrow @nogc @system inout(Char)[] `fromStringz`(Char)(return scope inout(Char)* `cString`)
if (isSomeChar!Char);
pure nothrow @nogc @safe inout(Char)[] `fromStringz`(Char)(return scope inout(Char)[] `cString`)
if (isSomeChar!Char);
  Parameters:

  inout(Char)* `cString` | A null-terminated c-style string.

  Returns:
  A D-style array of char, wchar or dchar referencing the same string. The returned array will retain the same type qualifiers as the input.
  Important Note: The returned array is a slice of the original buffer. The original data is not changed and not copied.
  Examples:

      writeln(fromStringz("foo\0"c.ptr)); // "foo"c
      writeln(fromStringz("foo\0"w.ptr)); // "foo"w
      writeln(fromStringz("foo\0"d.ptr)); // "foo"d

      writeln(fromStringz("福\0"c.ptr)); // "福"c
      writeln(fromStringz("福\0"w.ptr)); // "福"w
      writeln(fromStringz("福\0"d.ptr)); // "福"d

  Examples:

      struct C
      {
          char[32] name;
      }
      writeln(C("foo\0"c).name.fromStringz()); // "foo"c

      struct W
      {
          wchar[32] name;
      }
      writeln(W("foo\0"w).name.fromStringz()); // "foo"w

      struct D
      {
          dchar[32] name;
      }
      writeln(D("foo\0"d).name.fromStringz()); // "foo"d

pure nothrow @trusted immutable(char)* `toStringz`(scope const(char)[] `s`);
  Parameters:

  const(char)[] `s` | A D-style string.

  Returns:
  A C-style null-terminated string equivalent to `s`. `s` must not contain embedded '\0''s as any C function will treat the first '\0' that it sees as the end of the string. If `s`.empty is true, then a string containing only '\0' is returned.
  Important Note: When passing a char* to a C function, and the C function keeps it around for any reason, make sure that you keep a reference to it in your D code. Otherwise, it may become invalid during a garbage collection cycle and cause a nasty bug when the C code tries to use it.
  Examples:

      import core.stdc.string : strlen;
      import std.conv : to;

      auto p = toStringz("foo");
      writeln(strlen(p)); // 3
      const(char)[] foo = "abbzxyzzy";
      p = toStringz(foo[3 .. 5]);
      writeln(strlen(p)); // 2

      string test = "";
      p = toStringz(test);
      writeln(*p); // 0

      test = "\0";
      p = toStringz(test);
      writeln(*p); // 0

      test = "foo\0";
      p = toStringz(test);
      assert(p[0] == 'f' && p[1] == 'o' && p[2] == 'o' && p[3] == 0);

      const string test2 = "";
      p = toStringz(test2);
      writeln(*p); // 0

      assert(toStringz([]) is toStringz(""));

alias `CaseSensitive` = std.typecons.Flag!"caseSensitive".Flag;
  Flag indicating whether a search is case-sensitive.
ptrdiff_t `indexOf`(Range)(Range `s`, dchar `c`, CaseSensitive `cs` = Yes.caseSensitive)
if (isInputRange!Range && isSomeChar!(ElementType!Range) && !isSomeString!Range);
ptrdiff_t `indexOf`(C)(scope const(C)[] `s`, dchar `c`, CaseSensitive `cs` = Yes.caseSensitive)
if (isSomeChar!C);
ptrdiff_t `indexOf`(Range)(Range `s`, dchar `c`, size_t `startIdx`, CaseSensitive `cs` = Yes.caseSensitive)
if (isInputRange!Range && isSomeChar!(ElementType!Range) && !isSomeString!Range);
ptrdiff_t `indexOf`(C)(scope const(C)[] `s`, dchar `c`, size_t `startIdx`, CaseSensitive `cs` = Yes.caseSensitive)
if (isSomeChar!C);
  Searches for a character in a string or range.
  Parameters:

  Range `s` | string or InputRange of characters to search for `c` in
  dchar `c` | character to search for in `s`
  size_t `startIdx` | index to a well-formed code point in `s` to start searching from; defaults to 0
  CaseSensitive `cs` | specifies whether comparisons are case-sensitive (Yes.caseSensitive) or not (No.caseSensitive).

  Returns:
  If `c` is found in `s`, then the index of its first occurrence is returned. If `c` is not found or `startIdx` is greater than or equal to `s`.length, then -1 is returned. If the parameters are not valid UTF, the result will still be either -1 or in the range [`startIdx` .. `s`.length], but will not be reliable otherwise.
  Throws:
  If the sequence starting at `startIdx` does not represent a well-formed code point, then a std.utf.UTFException may be thrown.
  See Also:
  std.algorithm.searching.countUntil
  Examples:

      import std.typecons : No;

      string s = "Hello World";
      writeln(indexOf(s, 'W')); // 6
      writeln(indexOf(s, 'Z')); // -1
      writeln(indexOf(s, 'w', No.caseSensitive)); // 6

  Examples:

      import std.typecons : No;

      string s = "Hello World";
      writeln(indexOf(s, 'W', 4)); // 6
      writeln(indexOf(s, 'Z', 100)); // -1
      writeln(indexOf(s, 'w', 3, No.caseSensitive)); // 6

ptrdiff_t `indexOf`(Range, Char)(Range `s`, const(Char)[] `sub`)
if (isForwardRange!Range && isSomeChar!(ElementEncodingType!Range) && isSomeChar!Char);
ptrdiff_t `indexOf`(Range, Char)(Range `s`, const(Char)[] `sub`, in CaseSensitive `cs`)
if (isForwardRange!Range && isSomeChar!(ElementEncodingType!Range) && isSomeChar!Char);
@safe ptrdiff_t `indexOf`(Char1, Char2)(const(Char1)[] `s`, const(Char2)[] `sub`, in size_t `startIdx`)
if (isSomeChar!Char1 && isSomeChar!Char2);
@safe ptrdiff_t `indexOf`(Char1, Char2)(const(Char1)[] `s`, const(Char2)[] `sub`, in size_t `startIdx`, in CaseSensitive `cs`)
if (isSomeChar!Char1 && isSomeChar!Char2);
  Searches for a substring in a string or range.
  Parameters:

  Range `s` | string or ForwardRange of characters to search for `sub` in
  const(Char)[] `sub` | substring to search for in `s`
  size_t `startIdx` | index to a well-formed code point in `s` to start searching from; defaults to 0
  CaseSensitive `cs` | specifies whether comparisons are case-sensitive (Yes.caseSensitive) or not (No.caseSensitive)

  Returns:
  The index of the first occurrence of `sub` in `s`. If `sub` is not found or `startIdx` is greater than or equal to `s`.length, then -1 is returned. If the arguments are not valid UTF, the result will still be either -1 or in the range [`startIdx` .. `s`.length], but will not be reliable otherwise.
  Throws:
  If the sequence starting at `startIdx` does not represent a well-formed code point, then a std.utf.UTFException may be thrown.
  Bugs:
  Does not work with case-insensitive strings where the mapping of std.uni.toLower and std.uni.toUpper is not 1:1.
  Examples:

      import std.typecons : No;

      string s = "Hello World";
      writeln(indexOf(s, "Wo", 4)); // 6
      writeln(indexOf(s, "Zo", 100)); // -1
      writeln(indexOf(s, "wo", 3, No.caseSensitive)); // 6

  Examples:

      import std.typecons : No;

      string s = "Hello World";
      writeln(indexOf(s, "Wo")); // 6
      writeln(indexOf(s, "Zo")); // -1
      writeln(indexOf(s, "wO", No.caseSensitive)); // 6

pure @safe ptrdiff_t `lastIndexOf`(Char)(const(Char)[] `s`, in dchar `c`, in CaseSensitive `cs` = Yes.caseSensitive)
if (isSomeChar!Char);
pure @safe ptrdiff_t `lastIndexOf`(Char)(const(Char)[] `s`, in dchar `c`, in size_t `startIdx`, in CaseSensitive `cs` = Yes.caseSensitive)
if (isSomeChar!Char);
  Searches for the last occurrence of a character in a string.
  Parameters:

  const(Char)[] `s` | string to search for `c` in
  dchar `c` | character to search for in `s`
  size_t `startIdx` | index of a well-formed code point in `s` to start searching from; defaults to 0
  CaseSensitive `cs` | specifies whether comparisons are case-sensitive (Yes.caseSensitive) or not (No.caseSensitive)

  Returns:
  If `c` is found in `s`, then the index of its last occurrence is returned. If `c` is not found or `startIdx` is greater than or equal to `s`.length, then -1 is returned. If the parameters are not valid UTF, the result will still be either -1 or in the range [`startIdx` .. `s`.length], but will not be reliable otherwise.
  Throws:
  If the sequence ending at `startIdx` does not represent a well-formed code point, then a std.utf.UTFException may be thrown.
  Examples:

      import std.typecons : No;

      string s = "Hello World";
      writeln(lastIndexOf(s, 'l')); // 9
      writeln(lastIndexOf(s, 'Z')); // -1
      writeln(lastIndexOf(s, 'L', No.caseSensitive)); // 9

  Examples:

      import std.typecons : No;

      string s = "Hello World";
      writeln(lastIndexOf(s, 'l', 4)); // 3
      writeln(lastIndexOf(s, 'Z', 1337)); // -1
      writeln(lastIndexOf(s, 'L', 7, No.caseSensitive)); // 3

pure @safe ptrdiff_t `lastIndexOf`(Char1, Char2)(const(Char1)[] `s`, const(Char2)[] `sub`, in CaseSensitive `cs` = Yes.caseSensitive)
if (isSomeChar!Char1 && isSomeChar!Char2);
pure @safe ptrdiff_t `lastIndexOf`(Char1, Char2)(const(Char1)[] `s`, const(Char2)[] `sub`, in size_t `startIdx`, in CaseSensitive `cs` = Yes.caseSensitive)
if (isSomeChar!Char1 && isSomeChar!Char2);
  Searches for the last occurrence of a substring in a string.
  Parameters:

  const(Char1)[] `s` | string to search for `sub` in
  const(Char2)[] `sub` | substring to search for in `s`
  size_t `startIdx` | index to a well-formed code point in `s` to start searching from; defaults to 0
  CaseSensitive `cs` | specifies whether comparisons are case-sensitive (Yes.caseSensitive) or not (No.caseSensitive)

  Returns:
  The index of the last occurrence of `sub` in `s`. If `sub` is not found or `startIdx` is greater than or equal to `s`.length, then -1 is returned. If the parameters are not valid UTF, the result will still be either -1 or in the range [`startIdx` .. `s`.length], but will not be reliable otherwise.
  Throws:
  If the sequence starting at `startIdx` does not represent a well-formed code point, then a std.utf.UTFException may be thrown.
  Bugs:
  Does not work with case-insensitive strings where the mapping of std.uni.toLower and std.uni.toUpper is not 1:1.
  Examples:

      import std.typecons : No;

      string s = "Hello World";
      writeln(lastIndexOf(s, "ll")); // 2
      writeln(lastIndexOf(s, "Zo")); // -1
      writeln(lastIndexOf(s, "lL", No.caseSensitive)); // 2

  Examples:

      import std.typecons : No;

      string s = "Hello World";
      writeln(lastIndexOf(s, "ll", 4)); // 2
      writeln(lastIndexOf(s, "Zo", 128)); // -1
      writeln(lastIndexOf(s, "lL", 3, No.caseSensitive)); // -1

pure @safe ptrdiff_t `indexOfAny`(Char, Char2)(const(Char)[] `haystack`, const(Char2)[] `needles`, in CaseSensitive `cs` = Yes.caseSensitive)
if (isSomeChar!Char && isSomeChar!Char2);
pure @safe ptrdiff_t `indexOfAny`(Char, Char2)(const(Char)[] `haystack`, const(Char2)[] `needles`, in size_t `startIdx`, in CaseSensitive `cs` = Yes.caseSensitive)
if (isSomeChar!Char && isSomeChar!Char2);
  Searches the string `haystack` for one of the characters in `needles` starting at index `startIdx`. If `startIdx` is not given, it defaults to 0.
  Parameters:

  const(Char)[] `haystack` | string to search for needles in
  const(Char2)[] `needles` | characters to search for in `haystack`
  size_t `startIdx` | index of a well-formed code point in `haystack` to start searching from; defaults to 0
  CaseSensitive `cs` | specifies whether comparisons are case-sensitive (Yes.caseSensitive) or not (No.caseSensitive)

  Returns:
  The index of the first occurrence of any of the elements of `needles` in `haystack`. If no element of `needles` is found or `startIdx` is greater than or equal to `haystack`.length, then -1 is returned. If the parameters are not valid UTF, the result will still be either -1 or in the range [`startIdx` .. `haystack`.length], but will not be reliable otherwise.
  Throws:
  If the sequence starting at `startIdx` does not represent a well-formed code point, then a std.utf.UTFException may be thrown.
  Examples:

      import std.conv : to;

      ptrdiff_t i = "helloWorld".indexOfAny("Wr");
      writeln(i); // 5
      i = "öällo world".indexOfAny("lo ");
      writeln(i); // 4

  Examples:

      import std.conv : to;

      ptrdiff_t i = "helloWorld".indexOfAny("Wr", 4);
      writeln(i); // 5

      i = "Foo öällo world".indexOfAny("lh", 3);
      writeln(i); // 8

pure @safe ptrdiff_t `lastIndexOfAny`(Char, Char2)(const(Char)[] `haystack`, const(Char2)[] `needles`, in CaseSensitive `cs` = Yes.caseSensitive)
if (isSomeChar!Char && isSomeChar!Char2);
pure @safe ptrdiff_t `lastIndexOfAny`(Char, Char2)(const(Char)[] `haystack`, const(Char2)[] `needles`, in size_t `stopIdx`, in CaseSensitive `cs` = Yes.caseSensitive)
if (isSomeChar!Char && isSomeChar!Char2);
  Searches `haystack` for the last occurrence of any of the characters in `needles`.
  Parameters:

  const(Char)[] `haystack` | string to search needles in
  const(Char2)[] `needles` | characters to search for in `haystack`
  size_t `stopIdx` | index in `haystack` to stop searching at (exclusive); defaults to `haystack`.length
  CaseSensitive `cs` | specifies whether comparisons are case-sensitive (Yes.caseSensitive) or not (No.caseSensitive)

  Returns:
  The index of the last occurrence of any of the characters of `needles` in `haystack`. If no character of `needles` is found or `stopIdx` is 0, then -1 is returned. If the parameters are not valid UTF, the result will still be in the range [-1 .. `stopIdx`], but will not be reliable otherwise.
  Examples:

      ptrdiff_t i = "helloWorld".lastIndexOfAny("Wlo");
      writeln(i); // 8

      i = "Foo öäöllo world".lastIndexOfAny("öF");
      writeln(i); // 8

  Examples:

      import std.conv : to;

      ptrdiff_t i = "helloWorld".lastIndexOfAny("Wlo", 4);
      writeln(i); // 3

      i = "Foo öäöllo world".lastIndexOfAny("öF", 3);
      writeln(i); // 0

pure @safe ptrdiff_t `indexOfNeither`(Char, Char2)(const(Char)[] `haystack`, const(Char2)[] `needles`, in CaseSensitive `cs` = Yes.caseSensitive)
if (isSomeChar!Char && isSomeChar!Char2);
pure @safe ptrdiff_t `indexOfNeither`(Char, Char2)(const(Char)[] `haystack`, const(Char2)[] `needles`, in size_t `startIdx`, in CaseSensitive `cs` = Yes.caseSensitive)
if (isSomeChar!Char && isSomeChar!Char2);
  Searches `haystack` for a character not in `needles`.
  Parameters:

  const(Char)[] `haystack` | string to search for needles in
  const(Char2)[] `needles` | characters to search for in `haystack`
  size_t `startIdx` | index of a well-formed code point in `haystack` to start searching from; defaults to 0
  CaseSensitive `cs` | specifies whether comparisons are case-sensitive (Yes.caseSensitive) or not (No.caseSensitive)

  Returns:
  The index of the first character in `haystack` that is not an element of `needles`. If all characters of `haystack` are elements of `needles` or `startIdx` is greater than or equal to `haystack`.length, then -1 is returned. If the parameters are not valid UTF, the result will still be either -1 or in the range [`startIdx` .. `haystack`.length], but will not be reliable otherwise.
  Throws:
  If the sequence starting at `startIdx` does not represent a well-formed code point, then a std.utf.UTFException may be thrown.
  Examples:

      writeln(indexOfNeither("abba", "a", 2)); // 2
      writeln(indexOfNeither("def", "de", 1)); // 2
      writeln(indexOfNeither("dfefffg", "dfe", 4)); // 6

  Examples:

      writeln(indexOfNeither("def", "a")); // 0
      writeln(indexOfNeither("def", "de")); // 2
      writeln(indexOfNeither("dfefffg", "dfe")); // 6

pure @safe ptrdiff_t `lastIndexOfNeither`(Char, Char2)(const(Char)[] `haystack`, const(Char2)[] `needles`, in CaseSensitive `cs` = Yes.caseSensitive)
if (isSomeChar!Char && isSomeChar!Char2);
pure @safe ptrdiff_t `lastIndexOfNeither`(Char, Char2)(const(Char)[] `haystack`, const(Char2)[] `needles`, in size_t `stopIdx`, in CaseSensitive `cs` = Yes.caseSensitive)
if (isSomeChar!Char && isSomeChar!Char2);
  Searches for the last character in `haystack` that is not in `needles`.
  Parameters:

  const(Char)[] `haystack` | string to search for needles in
  const(Char2)[] `needles` | characters to search for in `haystack`
  size_t `stopIdx` | index in `haystack` to stop searching at (exclusive); defaults to `haystack`.length
  CaseSensitive `cs` | specifies whether comparisons are case-sensitive (Yes.caseSensitive) or not (No.caseSensitive)

  Returns:
  The index of the last character in `haystack` that is not an element of `needles`. If all characters of `haystack` are in `needles` or `stopIdx` is 0, then -1 is returned. If the parameters are not valid UTF, the result will still be in the range [-1 .. `stopIdx`], but will not be reliable otherwise.
  Examples:

      writeln(lastIndexOfNeither("abba", "a")); // 2
      writeln(lastIndexOfNeither("def", "f")); // 1

  Examples:

      writeln(lastIndexOfNeither("def", "rsa", 3)); // -1
      writeln(lastIndexOfNeither("abba", "a", 2)); // 1

pure nothrow @nogc @safe auto `representation`(Char)(Char[] `s`)
if (isSomeChar!Char);
  Returns the representation of a string, which has the same type as the string except the character type is replaced by ubyte, ushort, or uint depending on the character width.
  Parameters:

  Char[] `s` | The string to return the representation of.

  Returns:
  The representation of the passed string.
  Examples:

      string s = "hello";
      static assert(is(typeof(representation(s)) == immutable(ubyte)[]));
      assert(representation(s) is cast(immutable(ubyte)[]) s);
      writeln(representation(s)); // [0x68, 0x65, 0x6c, 0x6c, 0x6f]

pure @trusted S `capitalize`(S)(S `input`)
if (isSomeString!S);
  Capitalize the first character of s and convert the rest of s to lowercase.
  Parameters:

  S `input` | The string to capitalize.

  Returns:
  The capitalized string.
  See Also:
  std.uni.asCapitalized for a lazy range version that doesn't allocate memory
  Examples:

      writeln(capitalize("hello")); // "Hello"
      writeln(capitalize("World")); // "World"

alias `KeepTerminator` = std.typecons.Flag!"keepTerminator".Flag;
pure @safe C[][] `splitLines`(C)(C[] `s`, KeepTerminator `keepTerm` = No.keepTerminator)
if (isSomeChar!C);
  Split `s` into an array of lines according to the unicode standard using '\r', '\n', "\r\n", std.uni.lineSep, std.uni.paraSep, U+0085 (NEL), '\v' and '\f' as delimiters. If `keepTerm` is set to `KeepTerminator`.yes, then the delimiter is included in the strings returned.
  Does not throw on invalid UTF; such is simply passed unchanged to the output.
  Allocates memory; use lineSplitter for an alternative that does not.
  Adheres to Unicode 7.0.
  Parameters:

  C[] `s` | a string of chars, wchars, or dchars, or any custom type that casts to a string type
  `KeepTerminator` `keepTerm` | whether delimiter is included or not in the results

  Returns:
  array of strings, each element is a line that is a slice of `s`
  See Also:
  lineSplitter std.algorithm.splitter std.regex.splitter
  Examples:

      string s = "Hello\nmy\rname\nis";
      writeln(splitLines(s)); // ["Hello", "my", "name", "is"]

auto `lineSplitter`(KeepTerminator keepTerm = No.keepTerminator, Range)(Range `r`)
if (hasSlicing!Range && hasLength!Range && isSomeChar!(ElementType!Range) && !isSomeString!Range);
auto `lineSplitter`(KeepTerminator keepTerm = No.keepTerminator, C)(C[] `r`)
if (isSomeChar!C);
  Split an array or slicable range of characters into a range of lines using '\`r`', '\n', '\v', '\f', "\`r`\n", std.uni.lineSep, std.uni.paraSep and '\u0085' (NEL) as delimiters. If keepTerm is set to Yes.keepTerminator, then the delimiter is included in the slices returned.
  Does not throw on invalid UTF; such is simply passed unchanged to the output.
  Adheres to Unicode 7.0.
  Does not allocate memory.
  Parameters:

  Range `r` | array of chars, wchars, or dchars or a slicable range
  keepTerm | whether delimiter is included or not in the results

  Returns:
  range of slices of the input range `r`
  See Also:
  splitLines std.algorithm.splitter std.regex.splitter
  Examples:

      import std.array : array;

      string s = "Hello\nmy\rname\nis";

      /* notice the call to 'array' to turn the lazy range created by
      lineSplitter comparable to the string[] created by splitLines.
      */
      writeln(lineSplitter(s).array); // splitLines(s)

  Examples:

      auto s = "\rpeter\n\rpaul\r\njerry\u2028ice\u2029cream\n\nsunday\nmon\u2030day\n";
      auto lines = s.lineSplitter();
      static immutable witness = ["", "peter", "", "paul", "jerry", "ice", "cream", "", "sunday", "mon\u2030day"];
      uint i;
      foreach (line; lines)
      {
          writeln(line); // witness[i++]
      }
      writeln(i); // witness.length

auto `stripLeft`(Range)(Range `input`)
if (isForwardRange!Range && isSomeChar!(ElementEncodingType!Range) && !isInfinite!Range && !isConvertibleToString!Range);
auto `stripLeft`(Range, Char)(Range `input`, const(Char)[] `chars`)
if ((isForwardRange!Range && isSomeChar!(ElementEncodingType!Range) || isConvertibleToString!Range) && isSomeChar!Char);
  Strips leading whitespace (as defined by std.uni.isWhite) or as specified in the second argument.
  Parameters:

  Range `input` | string or forward range of characters
  const(Char)[] `chars` | string of characters to be stripped

  Returns:
  `input` stripped of leading whitespace or characters specified in the second argument.

  Postconditions `input` and the returned value will share the same tail (see std.array.sameTail).

  See Also:
  Generic stripping on ranges: std.algorithm.mutation.stripLeft
  Examples:

      import std.uni : lineSep, paraSep;
      assert(stripLeft("     hello world     ") ==
             "hello world     ");
      assert(stripLeft("\n\t\v\rhello world\n\t\v\r") ==
             "hello world\n\t\v\r");
      assert(stripLeft(" \u2028hello world") ==
             "hello world");
      assert(stripLeft("hello world") ==
             "hello world");
      assert(stripLeft([lineSep] ~ "hello world" ~ lineSep) ==
             "hello world" ~ [lineSep]);
      assert(stripLeft([paraSep] ~ "hello world" ~ paraSep) ==
             "hello world" ~ [paraSep]);

      import std.array : array;
      import std.utf : byChar;
      assert(stripLeft("     hello world     "w.byChar).array ==
             "hello world     ");
      assert(stripLeft("     \u2022hello world     ".byChar).array ==
             "\u2022hello world     ");

  Examples:

      assert(stripLeft("     hello world     ", " ") ==
             "hello world     ");
      assert(stripLeft("xxxxxhello world     ", "x") ==
             "hello world     ");
      assert(stripLeft("xxxyy    hello world     ", "xy ") ==
             "hello world     ");

  Examples:

      import std.array : array;
      import std.utf : byChar, byWchar, byDchar;

      assert(stripLeft("  xxxyy hello world     "w.byChar, "xy ").array ==
             "hello world     ");

      assert(stripLeft("\u2028\u2020hello world\u2028"w.byWchar,
                       "\u2028").array == "\u2020hello world\u2028");
      assert(stripLeft("\U00010001hello world"w.byWchar, " ").array ==
             "\U00010001hello world"w);
      assert(stripLeft("\U00010001 xyhello world"d.byDchar,
                       "\U00010001 xy").array == "hello world"d);

      writeln(stripLeft("\u2020hello"w, "\u2020"w)); // "hello"w
      writeln(stripLeft("\U00010001hello"d, "\U00010001"d)); // "hello"d
      writeln(stripLeft(" hello ", "")); // " hello "

auto `stripRight`(Range)(Range `str`)
if (isSomeString!Range || isRandomAccessRange!Range && hasLength!Range && hasSlicing!Range && !isConvertibleToString!Range && isSomeChar!(ElementEncodingType!Range));
auto `stripRight`(Range, Char)(Range `str`, const(Char)[] `chars`)
if ((isBidirectionalRange!Range && isSomeChar!(ElementEncodingType!Range) || isConvertibleToString!Range) && isSomeChar!Char);
  Strips trailing whitespace (as defined by std.uni.isWhite) or as specified in the second argument.
  Parameters:

  Range `str` | string or random access range of characters
  const(Char)[] `chars` | string of characters to be stripped

  Returns:
  slice of `str` stripped of trailing whitespace or characters specified in the second argument.
  See Also:
  Generic stripping on ranges: std.algorithm.mutation.stripRight
  Examples:

      import std.uni : lineSep, paraSep;
      assert(stripRight("     hello world     ") ==
             "     hello world");
      assert(stripRight("\n\t\v\rhello world\n\t\v\r") ==
             "\n\t\v\rhello world");
      assert(stripRight("hello world") ==
             "hello world");
      assert(stripRight([lineSep] ~ "hello world" ~ lineSep) ==
             [lineSep] ~ "hello world");
      assert(stripRight([paraSep] ~ "hello world" ~ paraSep) ==
             [paraSep] ~ "hello world");

  Examples:

      assert(stripRight("     hello world     ", "x") ==
             "     hello world     ");
      assert(stripRight("     hello world     ", " ") ==
             "     hello world");
      assert(stripRight("     hello worldxy     ", "xy ") ==
             "     hello world");

auto `strip`(Range)(Range `str`)
if (isSomeString!Range || isRandomAccessRange!Range && hasLength!Range && hasSlicing!Range && !isConvertibleToString!Range && isSomeChar!(ElementEncodingType!Range));
auto `strip`(Range, Char)(Range `str`, const(Char)[] `chars`)
if ((isBidirectionalRange!Range && isSomeChar!(ElementEncodingType!Range) || isConvertibleToString!Range) && isSomeChar!Char);
auto `strip`(Range, Char)(Range `str`, const(Char)[] `leftChars`, const(Char)[] `rightChars`)
if ((isBidirectionalRange!Range && isSomeChar!(ElementEncodingType!Range) || isConvertibleToString!Range) && isSomeChar!Char);
  Strips both leading and trailing whitespace (as defined by std.uni.isWhite) or as specified in the second argument.
  Parameters:

  Range `str` | string or random access range of characters
  const(Char)[] `chars` | string of characters to be stripped
  const(Char)[] `leftChars` | string of leading characters to be stripped
  const(Char)[] `rightChars` | string of trailing characters to be stripped

  Returns:
  slice of `str` stripped of leading and trailing whitespace or characters as specified in the second argument.
  See Also:
  Generic stripping on ranges: std.algorithm.mutation.strip
  Examples:

      import std.uni : lineSep, paraSep;
      assert(strip("     hello world     ") ==
             "hello world");
      assert(strip("\n\t\v\rhello world\n\t\v\r") ==
             "hello world");
      assert(strip("hello world") ==
             "hello world");
      assert(strip([lineSep] ~ "hello world" ~ [lineSep]) ==
             "hello world");
      assert(strip([paraSep] ~ "hello world" ~ [paraSep]) ==
             "hello world");

  Examples:

      assert(strip("     hello world     ", "x") ==
             "     hello world     ");
      assert(strip("     hello world     ", " ") ==
             "hello world");
      assert(strip("   xyxyhello worldxyxy     ", "xy ") ==
             "hello world");
      writeln(strip("\u2020hello\u2020"w, "\u2020"w)); // "hello"w
      writeln(strip("\U00010001hello\U00010001"d, "\U00010001"d)); // "hello"d
      writeln(strip(" hello ", "")); // " hello "

  Examples:

      writeln(strip("xxhelloyy", "x", "y")); // "hello"
      assert(strip("   xyxyhello worldxyxyzz    ", "xy ", "xyz ") ==
             "hello world");
      writeln(strip("\u2020hello\u2028"w, "\u2020"w, "\u2028"w)); // "hello"w
      assert(strip("\U00010001hello\U00010002"d, "\U00010001"d, "\U00010002"d) ==
             "hello"d);
      writeln(strip(" hello ", "", "")); // " hello "

Range `chomp`(Range)(Range `str`)
if ((isRandomAccessRange!Range && isSomeChar!(ElementEncodingType!Range) || isNarrowString!Range) && !isConvertibleToString!Range);
Range `chomp`(Range, C2)(Range `str`, const(C2)[] `delimiter`)
if ((isBidirectionalRange!Range && isSomeChar!(ElementEncodingType!Range) || isNarrowString!Range) && !isConvertibleToString!Range && isSomeChar!C2);
  If `str` ends with `delimiter`, then `str` is returned without `delimiter` on its end. If it `str` does not end with `delimiter`, then it is returned unchanged.
  If no `delimiter` is given, then one trailing '\r', '\n', "\r\n", '\f', '\v', std.uni.lineSep, std.uni.paraSep, or std.uni.nelSep is removed from the end of `str`. If `str` does not end with any of those characters, then it is returned unchanged.
  Parameters:

  Range `str` | string or indexable range of characters
  const(C2)[] `delimiter` | string of characters to be sliced off end of str[]

  Returns:
  slice of str
  Examples:

      import std.uni : lineSep, paraSep, nelSep;
      import std.utf : decode;
      writeln(chomp(" hello world  \n\r")); // " hello world  \n"
      writeln(chomp(" hello world  \r\n")); // " hello world  "
      writeln(chomp(" hello world  \f")); // " hello world  "
      writeln(chomp(" hello world  \v")); // " hello world  "
      writeln(chomp(" hello world  \n\n")); // " hello world  \n"
      writeln(chomp(" hello world  \n\n ")); // " hello world  \n\n "
      writeln(chomp(" hello world  \n\n" ~ [lineSep])); // " hello world  \n\n"
      writeln(chomp(" hello world  \n\n" ~ [paraSep])); // " hello world  \n\n"
      writeln(chomp(" hello world  \n\n" ~ [nelSep])); // " hello world  \n\n"
      writeln(chomp(" hello world ")); // " hello world "
      writeln(chomp(" hello world")); // " hello world"
      writeln(chomp("")); // ""

      writeln(chomp(" hello world", "orld")); // " hello w"
      writeln(chomp(" hello world", " he")); // " hello world"
      writeln(chomp("", "hello")); // ""

      // Don't decode pointlessly
      writeln(chomp("hello\xFE", "\r")); // "hello\xFE"

Range `chompPrefix`(Range, C2)(Range `str`, const(C2)[] `delimiter`)
if ((isForwardRange!Range && isSomeChar!(ElementEncodingType!Range) || isNarrowString!Range) && !isConvertibleToString!Range && isSomeChar!C2);
  If `str` starts with `delimiter`, then the part of `str` following `delimiter` is returned. If `str` does not start with
  `delimiter`, then it is returned unchanged.
  Parameters:

  Range `str` | string or forward range of characters
  const(C2)[] `delimiter` | string of characters to be sliced off front of str[]

  Returns:
  slice of str
  Examples:

      writeln(chompPrefix("hello world", "he")); // "llo world"
      writeln(chompPrefix("hello world", "hello w")); // "orld"
      writeln(chompPrefix("hello world", " world")); // "hello world"
      writeln(chompPrefix("", "hello")); // ""

Range `chop`(Range)(Range `str`)
if ((isBidirectionalRange!Range && isSomeChar!(ElementEncodingType!Range) || isNarrowString!Range) && !isConvertibleToString!Range);
  Returns `str` without its last character, if there is one. If `str` ends with "\r\n", then both are removed. If `str` is empty, then it is returned unchanged.
  Parameters:

  Range `str` | string (must be valid UTF)

  Returns:
  slice of str
  Examples:

      writeln(chop("hello world")); // "hello worl"
      writeln(chop("hello world\n")); // "hello world"
      writeln(chop("hello world\r")); // "hello world"
      writeln(chop("hello world\n\r")); // "hello world\n"
      writeln(chop("hello world\r\n")); // "hello world"
      writeln(chop("Walter Bright")); // "Walter Brigh"
      writeln(chop("")); // ""

S `leftJustify`(S)(S `s`, size_t `width`, dchar `fillChar` = ' ')
if (isSomeString!S);
  Left justify `s` in a field `width` characters wide. `fillChar` is the character that will be used to fill up the space in the field that `s` doesn't fill.
  Parameters:

  S `s` | string
  size_t `width` | minimum field width
  dchar `fillChar` | used to pad end up to `width` characters

  Returns:
  GC allocated string
  See Also:
  leftJustifier, which does not allocate
  Examples:

      writeln(leftJustify("hello", 7, 'X')); // "helloXX"
      writeln(leftJustify("hello", 2, 'X')); // "hello"
      writeln(leftJustify("hello", 9, 'X')); // "helloXXXX"

auto `leftJustifier`(Range)(Range `r`, size_t `width`, dchar `fillChar` = ' ')
if (isInputRange!Range && isSomeChar!(ElementEncodingType!Range) && !isConvertibleToString!Range);
  Left justify s in a field `width` characters wide. `fillChar` is the character that will be used to fill up the space in the field that s doesn't fill.
  Parameters:

  Range `r` | string or range of characters
  size_t `width` | minimum field width
  dchar `fillChar` | used to pad end up to `width` characters

  Returns:
  a lazy range of the left justified result
  See Also:
  rightJustifier
  Examples:

      import std.algorithm.comparison : equal;
      import std.utf : byChar;
      assert(leftJustifier("hello", 2).equal("hello".byChar));
      assert(leftJustifier("hello", 7).equal("hello  ".byChar));
      assert(leftJustifier("hello", 7, 'x').equal("helloxx".byChar));

S `rightJustify`(S)(S `s`, size_t `width`, dchar `fillChar` = ' ')
if (isSomeString!S);
  Right justify `s` in a field `width` characters wide. `fillChar` is the character that will be used to fill up the space in the field that `s` doesn't fill.
  Parameters:

  S `s` | string
  size_t `width` | minimum field width
  dchar `fillChar` | used to pad end up to `width` characters

  Returns:
  GC allocated string
  See Also:
  rightJustifier, which does not allocate
  Examples:

      writeln(rightJustify("hello", 7, 'X')); // "XXhello"
      writeln(rightJustify("hello", 2, 'X')); // "hello"
      writeln(rightJustify("hello", 9, 'X')); // "XXXXhello"

auto `rightJustifier`(Range)(Range `r`, size_t `width`, dchar `fillChar` = ' ')
if (isForwardRange!Range && isSomeChar!(ElementEncodingType!Range) && !isConvertibleToString!Range);
  Right justify s in a field `width` characters wide. `fillChar` is the character that will be used to fill up the space in the field that s doesn't fill.
  Parameters:

  Range `r` | string or forward range of characters
  size_t `width` | minimum field width
  dchar `fillChar` | used to pad end up to `width` characters

  Returns:
  a lazy range of the right justified result
  See Also:
  leftJustifier
  Examples:

      import std.algorithm.comparison : equal;
      import std.utf : byChar;
      assert(rightJustifier("hello", 2).equal("hello".byChar));
      assert(rightJustifier("hello", 7).equal("  hello".byChar));
      assert(rightJustifier("hello", 7, 'x').equal("xxhello".byChar));

S `center`(S)(S `s`, size_t `width`, dchar `fillChar` = ' ')
if (isSomeString!S);
  Center `s` in a field `width` characters wide. `fillChar` is the character that will be used to fill up the space in the field that `s` doesn't fill.
  Parameters:

  S `s` | The string to center
  size_t `width` | Width of the field to center `s` in
  dchar `fillChar` | The character to use for filling excess space in the field

  Returns:
  The resulting center-justified string. The returned string is GC-allocated. To avoid GC allocation, use centerJustifier instead.
  Examples:

      writeln(center("hello", 7, 'X')); // "XhelloX"
      writeln(center("hello", 2, 'X')); // "hello"
      writeln(center("hello", 9, 'X')); // "XXhelloXX"

auto `centerJustifier`(Range)(Range `r`, size_t `width`, dchar `fillChar` = ' ')
if (isForwardRange!Range && isSomeChar!(ElementEncodingType!Range) && !isConvertibleToString!Range);
  Center justify `r` in a field `width` characters wide. `fillChar` is the character that will be used to fill up the space in the field that `r` doesn't fill.
  Parameters:

  Range `r` | string or forward range of characters
  size_t `width` | minimum field width
  dchar `fillChar` | used to pad end up to `width` characters

  Returns:
  a lazy range of the center justified result
  See Also:
  leftJustifier rightJustifier
  Examples:

      import std.algorithm.comparison : equal;
      import std.utf : byChar;
      assert(centerJustifier("hello", 2).equal("hello".byChar));
      assert(centerJustifier("hello", 8).equal(" hello  ".byChar));
      assert(centerJustifier("hello", 7, 'x').equal("xhellox".byChar));

pure auto `detab`(Range)(auto ref Range `s`, size_t `tabSize` = 8)
if (isForwardRange!Range && isSomeChar!(ElementEncodingType!Range) || __traits(compiles, StringTypeOf!Range));
  Replace each tab character in `s` with the number of spaces necessary to align the following character at the next tab stop.
  Parameters:

  Range `s` | string
  size_t `tabSize` | distance between tab stops

  Returns:
  GC allocated string with tabs replaced with spaces
  Examples:

      writeln(detab(" \n\tx", 9)); // " \n         x"

auto `detabber`(Range)(Range `r`, size_t `tabSize` = 8)
if (isForwardRange!Range && isSomeChar!(ElementEncodingType!Range) && !isConvertibleToString!Range);
auto `detabber`(Range)(auto ref Range `r`, size_t `tabSize` = 8)
if (isConvertibleToString!Range);
  Replace each tab character in `r` with the number of spaces necessary to align the following character at the next tab stop.
  Parameters:

  Range `r` | string or forward range
  size_t `tabSize` | distance between tab stops

  Returns:
  lazy forward range with tabs replaced with spaces
  Examples:

      import std.array : array;

      writeln(detabber(" \n\tx", 9).array); // " \n         x"

  Examples:

      import std.array : array;
      import std.utf : byChar, byWchar;

      writeln(detabber(" \u2029\t".byChar, 9).array); // " \u2029         "
      auto r = "hel\tx".byWchar.detabber();
      writeln(r.front); // 'h'
      auto s = r.save;
      r.popFront();
      r.popFront();
      writeln(r.front); // 'l'
      writeln(s.front); // 'h'

auto `entab`(Range)(Range `s`, size_t `tabSize` = 8)
if (isForwardRange!Range && isSomeChar!(ElementEncodingType!Range));
  Replaces spaces in `s` with the optimal number of tabs. All spaces and tabs at the end of a line are removed.
  Parameters:

  Range `s` | String to convert.
  size_t `tabSize` | Tab columns are `tabSize` spaces apart.

  Returns:
  GC allocated string with spaces replaced with tabs; use entabber to not allocate.
  See Also:
  entabber
  Examples:

      writeln(entab("        x \n")); // "\tx\n"

auto `entabber`(Range)(Range `r`, size_t `tabSize` = 8)
if (isForwardRange!Range && !isConvertibleToString!Range);
  Replaces spaces in range `r` with the optimal number of tabs. All spaces and tabs at the end of a line are removed.
  Parameters:

  Range `r` | string or forward range
  size_t `tabSize` | distance between tab stops

  Returns:
  lazy forward range with spaces replaced with tabs
  See Also:
  entab
  Examples:

      import std.array : array;
      writeln(entabber("        x \n").array); // "\tx\n"

pure @safe C1[] `translate`(C1, C2 = immutable(char))(C1[] `str`, in dchar[dchar] `transTable`, const(C2)[] `toRemove` = null)
if (isSomeChar!C1 && isSomeChar!C2);
pure @safe C1[] `translate`(C1, S, C2 = immutable(char))(C1[] `str`, in S[dchar] `transTable`, const(C2)[] `toRemove` = null)
if (isSomeChar!C1 && isSomeString!S && isSomeChar!C2);
  Replaces the characters in `str` which are keys in `transTable` with their corresponding values in `transTable`. `transTable` is an AA where its keys are dchar and its values are either dchar or some type of string. Also, if `toRemove` is given, the characters in it are removed from `str` prior to translation. `str` itself is unaltered. A copy with the changes is returned.
  See Also:
  tr, std.array.replace, std.algorithm.iteration.substitute
  Parameters:

  C1[] `str` | The original string.
  dchar[dchar] `transTable` | The AA indicating which characters to replace and what to replace them with.
  const(C2)[] `toRemove` | The characters to remove from the string.

  Examples:

      dchar[dchar] transTable1 = ['e' : '5', 'o' : '7', '5': 'q'];
      writeln(translate("hello world", transTable1)); // "h5ll7 w7rld"

      writeln(translate("hello world", transTable1, "low")); // "h5 rd"

      string[dchar] transTable2 = ['e' : "5", 'o' : "orange"];
      writeln(translate("hello world", transTable2)); // "h5llorange worangerld"

void `translate`(C1, C2 = immutable(char), Buffer)(const(C1)[] `str`, in dchar[dchar] `transTable`, const(C2)[] `toRemove`, Buffer `buffer`)
if (isSomeChar!C1 && isSomeChar!C2 && isOutputRange!(Buffer, C1));
void `translate`(C1, S, C2 = immutable(char), Buffer)(C1[] `str`, in S[dchar] `transTable`, const(C2)[] `toRemove`, Buffer `buffer`)
if (isSomeChar!C1 && isSomeString!S && isSomeChar!C2 && isOutputRange!(Buffer, S));
  This is an overload of `translate` which takes an existing buffer to write the contents to.
  Parameters:

  const(C1)[] `str` | The original string.
  dchar[dchar] `transTable` | The AA indicating which characters to replace and what to replace them with.
  const(C2)[] `toRemove` | The characters to remove from the string.
  Buffer `buffer` | An output range to write the contents to.

  Examples:

      import std.array : appender;
      dchar[dchar] transTable1 = ['e' : '5', 'o' : '7', '5': 'q'];
      auto buffer = appender!(dchar[])();
      translate("hello world", transTable1, null, buffer);
      writeln(buffer.data); // "h5ll7 w7rld"

      buffer.clear();
      translate("hello world", transTable1, "low", buffer);
      writeln(buffer.data); // "h5 rd"

      buffer.clear();
      string[dchar] transTable2 = ['e' : "5", 'o' : "orange"];
      translate("hello world", transTable2, null, buffer);
      writeln(buffer.data); // "h5llorange worangerld"

pure nothrow @trusted C[] `translate`(C = immutable(char))(scope const(char)[] `str`, scope const(char)[] `transTable`, scope const(char)[] `toRemove` = null)
if (is(immutable(C) == immutable(char)));
  This is an ASCII-only overload of translate. It will not work with Unicode. It exists as an optimization for the cases where Unicode processing is not necessary.
  Unlike the other overloads of translate, this one does not take an AA. Rather, it takes a string generated by makeTransTable.
  The array generated by makeTransTable is 256 elements long such that the index is equal to the ASCII character being replaced and the value is equal to the character that it's being replaced with. Note that translate does not decode any of the characters, so you can actually pass it Extended ASCII characters if you want to (ASCII only actually uses 128 characters), but be warned that Extended ASCII characters are not valid Unicode and therefore will result in a UTFException being thrown from most other Phobos functions.
  Also, because no decoding occurs, it is possible to use this overload to translate ASCII characters within a proper UTF-8 string without altering the other, non-ASCII characters. It's replacing any code unit greater than 127 with another code unit or replacing any code unit with another code unit greater than 127 which will cause UTF validation issues.
  See Also:
  tr, std.array.replace, std.algorithm.iteration.substitute
  Parameters:

  const(char)[] `str` | The original string.
  const(char)[] `transTable` | The string indicating which characters to replace and what to replace them with. It is generated by makeTransTable.
  const(char)[] `toRemove` | The characters to remove from the string.

  Examples:

      auto transTable1 = makeTrans("eo5", "57q");
      writeln(translate("hello world", transTable1)); // "h5ll7 w7rld"

      writeln(translate("hello world", transTable1, "low")); // "h5 rd"

pure nothrow @trusted string `makeTrans`(scope const(char)[] `from`, scope const(char)[] `to`);
  Do same thing as makeTransTable but allocate the translation table on the GC heap.
  Use makeTransTable instead.
  Examples:

      auto transTable1 = makeTrans("eo5", "57q");
      writeln(translate("hello world", transTable1)); // "h5ll7 w7rld"

      writeln(translate("hello world", transTable1, "low")); // "h5 rd"

pure nothrow @nogc @safe char[256] `makeTransTable`(scope const(char)[] `from`, scope const(char)[] `to`);
  Construct 256 character translation table, where characters in from[] are replaced by corresponding characters in to[].
  Parameters:

  const(char)[] `from` | array of chars, less than or equal to 256 in length
  const(char)[] `to` | corresponding array of chars to translate to

  Returns:
  translation array
  Examples:

      writeln(translate("hello world", makeTransTable("hl", "q5"))); // "qe55o wor5d"
      writeln(translate("hello world", makeTransTable("12345", "67890"))); // "hello world"

pure @trusted void `translate`(C = immutable(char), Buffer)(scope const(char)[] `str`, scope const(char)[] `transTable`, scope const(char)[] `toRemove`, Buffer `buffer`)
if (is(immutable(C) == immutable(char)) && isOutputRange!(Buffer, char));
  This is an ASCII-only overload of `translate` which takes an existing buffer to write the contents to.
  Parameters:

  const(char)[] `str` | The original string.
  const(char)[] `transTable` | The string indicating which characters to replace and what to replace them with. It is generated by makeTransTable.
  const(char)[] `toRemove` | The characters to remove from the string.
  Buffer `buffer` | An output range to write the contents to.

  Examples:

      import std.array : appender;
      auto buffer = appender!(char[])();
      auto transTable1 = makeTransTable("eo5", "57q");
      translate("hello world", transTable1, null, buffer);
      writeln(buffer.data); // "h5ll7 w7rld"

      buffer.clear();
      translate("hello world", transTable1, "low", buffer);
      writeln(buffer.data); // "h5 rd"

pure @safe S `succ`(S)(S `s`)
if (isSomeString!S);
  Return string that is the 'successor' to s[]. If the rightmost character is a-zA-Z0-9, it is incremented within its case or digits. If it generates a carry, the process is repeated with the one to its immediate left.
  Examples:

      writeln(succ("1")); // "2"
      writeln(succ("9")); // "10"
      writeln(succ("999")); // "1000"
      writeln(succ("zz99")); // "aaa00"

C1[] `tr`(C1, C2, C3, C4 = immutable(char))(C1[] `str`, const(C2)[] `from`, const(C3)[] `to`, const(C4)[] `modifiers` = null);
  Replaces the characters in `str` which are in `from` with the the corresponding characters in `to` and returns the resulting string.
  `tr` is based on Posix's tr, though it doesn't do everything that the Posix utility does.
  Parameters:

  C1[] `str` | The original string.
  const(C2)[] `from` | The characters to replace.
  const(C3)[] `to` | The characters to replace with.
  const(C4)[] `modifiers` | String containing modifiers.

  Modifiers

  Modifier | Description
  'c' | Complement the list of characters in `from`
  'd' | Removes matching characters with no corresponding replacement in `to`
  's' | Removes adjacent duplicates in the replaced characters

  If the modifier 'd' is present, then the number of characters in `to` may be only 0 or 1.
  If the modifier 'd' is not present, and `to` is empty, then `to` is taken to be the same as `from`.
  If the modifier 'd' is not present, and `to` is shorter than `from`, then `to` is extended by replicating the last character in `to`.
  Both `from` and `to` may contain ranges using the '-' character (e.g. "a-d" is synonymous with "abcd".) Neither accept a leading '^' as meaning the complement of the string (use the 'c' modifier for that).
  See Also:
  translate, std.array.replace, std.algorithm.iteration.substitute
  Examples:

      writeln(tr("abcdef", "cd", "CD")); // "abCDef"
      writeln(tr("1st March, 2018", "March", "MAR", "s")); // "1st MAR, 2018"
      writeln(tr("abcdef", "ef", "", "d")); // "abcd"
      writeln(tr("14-Jul-87", "a-zA-Z", " ", "cs")); // " Jul "

bool `isNumeric`(S)(S `s`, bool `bAllowSep` = false)
if (isSomeString!S || isRandomAccessRange!S && hasSlicing!S && isSomeChar!(ElementType!S) && !isInfinite!S);
  Takes a string `s` and determines if it represents a number. This function also takes an optional parameter, `bAllowSep`, which will accept the separator characters ',' and '__' within the string. But these characters should be stripped from the string before using any of the conversion functions like to!int(), to!float(), and etc else an error will occur.
  Also please note, that no spaces are allowed within the string anywhere whether it's a leading, trailing, or embedded space(s), thus they too must be stripped from the string before using this function, or any of the conversion functions.
  Parameters:

  S `s` | the string or random access range to check
  bool `bAllowSep` | accept separator characters or not

  Returns:
  bool
  Examples:
  Integer Whole Number: (byte, ubyte, short, ushort, int, uint, long, and ulong) ['+'|'-']digit(s)[U|L|UL]

      assert(isNumeric("123"));
      assert(isNumeric("123UL"));
      assert(isNumeric("123L"));
      assert(isNumeric("+123U"));
      assert(isNumeric("-123L"));

  Examples:
  Floating-Point Number: (float, double, real, ifloat, idouble, and ireal) ['+'|'-']digit(s)[.][digit(s)][[e-|e+]digit(s)][i|f|L|Li|fi]] or [nan|nani|inf|-inf]

      assert(isNumeric("+123"));
      assert(isNumeric("-123.01"));
      assert(isNumeric("123.3e-10f"));
      assert(isNumeric("123.3e-10fi"));
      assert(isNumeric("123.3e-10L"));

      assert(isNumeric("nan"));
      assert(isNumeric("nani"));
      assert(isNumeric("-inf"));

  Examples:
  Floating-Point Number: (cfloat, cdouble, and creal) ['+'|'-']digit(s)[.][digit(s)][[e-|e+]digit(s)][+] [digit(s)[.][digit(s)][[e-|e+]digit(s)][i|f|L|Li|fi]] or [nan|nani|nan+nani|inf|-inf]

      assert(isNumeric("-123e-1+456.9e-10Li"));
      assert(isNumeric("+123e+10+456i"));
      assert(isNumeric("123+456"));

  Examples:
  isNumeric works with CTFE

      enum a = isNumeric("123.00E-5+1234.45E-12Li");
      enum b = isNumeric("12345xxxx890");

      static assert( a);
      static assert(!b);

char[4] `soundexer`(Range)(Range `str`)
if (isInputRange!Range && isSomeChar!(ElementEncodingType!Range) && !isConvertibleToString!Range);
char[4] `soundexer`(Range)(auto ref Range `str`)
if (isConvertibleToString!Range);
  Soundex algorithm.
  The Soundex algorithm converts a word into 4 characters based on how the word sounds phonetically. The idea is that two spellings that sound alike will have the same Soundex value, which means that Soundex can be used for fuzzy matching of names.
  Parameters:

  Range `str` | String or InputRange to convert to Soundex representation.

  Returns:
  The four character array with the Soundex result in it. The array has zero's in it if there is no Soundex representation for the string.
  See Also:
  Wikipedia, The Soundex Indexing System soundex

  Note Only works well with English names.

  Examples:

      writeln(soundexer("Gauss")); // "G200"
      writeln(soundexer("Ghosh")); // "G200"

      writeln(soundexer("Robert")); // "R163"
      writeln(soundexer("Rupert")); // "R163"

      writeln(soundexer("0123^&^^**&^")); // ['\0', '\0', '\0', '\0']

pure nothrow @safe char[] `soundex`(scope const(char)[] `str`, return scope char[] `buffer` = null);
  Like soundexer, but with different parameters and return value.
  Parameters:

  const(char)[] `str` | String to convert to Soundex representation.
  char[] `buffer` | Optional 4 char array to put the resulting Soundex characters into. If null, the return value buffer will be allocated on the heap.

  Returns:
  The four character array with the Soundex result in it. Returns null if there is no Soundex representation for the string.
  See Also:
  soundexer
  Examples:

      writeln(soundex("Gauss")); // "G200"
      writeln(soundex("Ghosh")); // "G200"

      writeln(soundex("Robert")); // "R163"
      writeln(soundex("Rupert")); // "R163"

      writeln(soundex("0123^&^^**&^")); // null

pure @safe string[string] `abbrev`(string[] `values`);
  Construct an associative array consisting of all abbreviations that uniquely map to the strings in values.
  This is useful in cases where the user is expected to type in one of a known set of strings, and the program will helpfully auto-complete the string once sufficient characters have been entered that uniquely identify it.
  Examples:

      import std.string;

      static string[] list = [ "food", "foxy" ];
      auto abbrevs = abbrev(list);
      assert(abbrevs == ["fox": "foxy", "food": "food",
                         "foxy": "foxy", "foo": "food"]);

size_t `column`(Range)(Range `str`, in size_t `tabsize` = 8)
if ((isInputRange!Range && isSomeChar!(ElementEncodingType!Range) || isNarrowString!Range) && !isConvertibleToString!Range);
  Compute column number at the end of the printed form of the string, assuming the string starts in the leftmost column, which is numbered starting from 0.
  Tab characters are expanded into enough spaces to bring the column number to the next multiple of tabsize. If there are multiple lines in the string, the column number of the last line is returned.
  Parameters:

  Range `str` | string or InputRange to be analyzed
  size_t `tabsize` | number of columns a tab character represents

  Returns:
  column number
  Examples:

      import std.utf : byChar, byWchar, byDchar;

      writeln(column("1234 ")); // 5
      writeln(column("1234 "w)); // 5
      writeln(column("1234 "d)); // 5

      writeln(column("1234 ".byChar())); // 5
      writeln(column("1234 "w.byWchar())); // 5
      writeln(column("1234 "d.byDchar())); // 5

      // Tab stops are set at 8 spaces by default; tab characters insert enough
      // spaces to bring the column position to the next multiple of 8.
      writeln(column("\t")); // 8
      writeln(column("1\t")); // 8
      writeln(column("\t1")); // 9
      writeln(column("123\t")); // 8

      // Other tab widths are possible by specifying it explicitly:
      writeln(column("\t", 4)); // 4
      writeln(column("1\t", 4)); // 4
      writeln(column("\t1", 4)); // 5
      writeln(column("123\t", 4)); // 4

      // New lines reset the column number.
      writeln(column("abc\n")); // 0
      writeln(column("abc\n1")); // 1
      writeln(column("abcdefg\r1234")); // 4
      writeln(column("abc\u20281")); // 1
      writeln(column("abc\u20291")); // 1
      writeln(column("abc\u00851")); // 1
      writeln(column("abc\u00861")); // 5

S `wrap`(S)(S `s`, in size_t `columns` = 80, S `firstindent` = null, S `indent` = null, in size_t `tabsize` = 8)
if (isSomeString!S);
  Wrap text into a paragraph.
  The input text string s is formed into a paragraph by breaking it up into a sequence of lines, delineated by \n, such that the number of columns is not exceeded on each line. The last line is terminated with a \n.
  Parameters:

  S `s` | text string to be wrapped
  size_t `columns` | maximum number of columns in the paragraph
  S `firstindent` | string used to indent first line of the paragraph
  S `indent` | string to use to indent following lines of the paragraph
  size_t `tabsize` | column spacing of tabs in firstindent[] and indent[]

  Returns:
  resulting paragraph as an allocated string
  Examples:

      writeln(wrap("a short string", 7)); // "a short\nstring\n"

      // wrap will not break inside of a word, but at the next space
      writeln(wrap("a short string", 4)); // "a\nshort\nstring\n"

      writeln(wrap("a short string", 7, "\t")); // "\ta\nshort\nstring\n"
      writeln(wrap("a short string", 7, "\t", "    ")); // "\ta\n    short\n    string\n"

pure @safe S `outdent`(S)(S `str`)
if (isSomeString!S);
  Removes one level of indentation from a multi-line string.
  This uniformly outdents the text as much as possible. Whitespace-only lines are always converted to blank lines.
  Does not allocate memory if it does not throw.
  Parameters:

  S `str` | multi-line string

  Returns:
  outdented string
  Throws:
  StringException if indentation is done with different sequences of whitespace characters.
  Examples:

      enum pretty = q{
         import std.stdio;
         void main() {
             writeln("Hello");
         }
      }.outdent();

      enum ugly = q{
      import std.stdio;
      void main() {
      writeln("Hello");
      }
      };

      writeln(pretty); // ugly

pure @safe S[] `outdent`(S)(return scope S[] `lines`)
if (isSomeString!S);
  Removes one level of indentation from an array of single-line strings.
  This uniformly outdents the text as much as possible. Whitespace-only lines are always converted to blank lines.
  Parameters:

  S[] `lines` | array of single-line strings

  Returns:
  lines[] is rewritten in place with outdented lines
  Throws:
  StringException if indentation is done with different sequences of whitespace characters.
  Examples:

      auto str1 = [
          "    void main()\n",
          "    {\n",
          "        test();\n",
          "    }\n"
      ];
      auto str1Expected = [
          "void main()\n",
          "{\n",
          "    test();\n",
          "}\n"
      ];
      writeln(str1.outdent); // str1Expected

      auto str2 = [
          "void main()\n",
          "    {\n",
          "            test();\n",
          "    }\n"
      ];
      writeln(str2.outdent); // str2

auto `assumeUTF`(T)(T[] `arr`)
if (staticIndexOf!(immutable(T), immutable(ubyte), immutable(ushort), immutable(uint)) != -1);
  Assume the given array of integers `arr` is a well-formed UTF string and return it typed as a UTF string.
  ubyte becomes char, ushort becomes wchar and uint becomes dchar. Type qualifiers are preserved.
  When compiled with debug mode, this function performs an extra check to make sure the return value is a valid Unicode string.
  Parameters:

  T[] `arr` | array of bytes, ubytes, shorts, ushorts, ints, or uints

  Returns:
  arr retyped as an array of chars, wchars, or dchars
  Throws:
  In debug mode AssertError, when the result is not a well-formed UTF string.
  See Also:
  representation
  Examples:

      string a = "Hölo World";
      immutable(ubyte)[] b = a.representation;
      string c = b.assumeUTF;

      writeln(c); // "Hölo World"

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