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Last update Sun Apr 19 16:54:23 2009

# std.string

String handling functions. 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 *string types are preferable because they don't exhibit undesired aliasing, thus making code more robust.

Authors:
Walter Bright, Andrei Alexandrescu

typedef StringException;
  Thrown on errors in string functions.

invariant char[16u] hexdigits;
  0..9A..F

invariant char[10u] digits;
  0..9

invariant char[8u] octdigits;
  0..7

invariant char[26u] lowercase;
  a..z

invariant char[26u] uppercase;
  A..Z

invariant char[52u] letters;
  A..Za..z

invariant char[6u] whitespace;
  ASCII whitespace

dchar LS;
  UTF line separator

dchar PS;
  UTF paragraph separator

invariant char[2u] newline;
  Newline sequence for this system

bool iswhite(dchar c);
  Returns true if c is whitespace

int cmp(C1, C2)(in C1[] s1, in C2[] s2);
int icmp(in char[] s1, in char[] s2);
  Compare two strings. cmp is case sensitive, icmp is case insensitive.

  Returns:
  < 0 | s1 < s2
  = 0 | s1 == s2
  > 0 | s1 > s2

const(char)* toStringz(const(char)[] s);
  Convert array of chars s[] to a C-style 0-terminated string. s[] must not contain embedded 0's.

int find(in char[] s, dchar c);
int ifind(in char[] s, dchar c);
int rfind(in char[] s, dchar c);
int irfind(in char[] s, dchar c);
  find, ifind find first occurrence of c in string s. rfind, irfind find last occurrence of c in string s.

  find, rfind are case sensitive; ifind, irfind are case insensitive.

  Returns:
  Index in s where c is found, -1 if not found.

int find(in char[] s, in char[] sub);
int ifind(in char[] s, in char[] sub);
int rfind(in char[] s, in char[] sub);
int irfind(in char[] s, in char[] sub);
  find, ifind find first occurrence of sub[] in string s[]. rfind, irfind find last occurrence of sub[] in string s[].

  find, rfind are case sensitive; ifind, irfind are case insensitive.

  Returns:
  Index in s where c is found, -1 if not found.

string tolower(string s);
  Convert string s[] to lower case.

void tolowerInPlace(C)(ref C[] s);
  Converts s to lowercase in place.

string toupper(string s);
  Convert string s[] to upper case.

void toupperInPlace(C)(ref C[] s);
  Converts s to uppercase in place.

string capitalize(string s);
  Capitalize first character of string s[], convert rest of string s[] to lower case.

string capwords(string s);
  Capitalize all words in string s[]. Remove leading and trailing whitespace. Replace all sequences of whitespace with a single space.

string repeat(string s, size_t n);
  Return a string that consists of s[] repeated n times.

string join(in immutable(char)[][] words, string sep);
  Concatenate all the strings in words[] together into one string; use sep[] as the separator.

immutable(char)[][] split(string s);
  Split s[] into an array of words, using whitespace as the delimiter.

immutable(char)[][] split(string s, string delim);
  Split s[] into an array of words, using delim[] as the delimiter.

immutable(char)[][] splitlines(string s);
  Split s[] into an array of lines, using CR, LF, or CR-LF as the delimiter. The delimiter is not included in the line.

String stripl(String)(String s);
String stripr(String)(String s);
String strip(String)(String s);
  Strips leading or trailing whitespace, or both.

bool startsWith(A1, A2)(A1 longer, A2 shorter);
  Returns true if and only if the array longer starts with array shorter.

bool endsWith(A1, A2)(A1 longer, A2 shorter);
  Returns true if and only if the array longer ends with array shorter.

C[] chomp(C)(C[] s, in C[] delimiter = null);
  Returns s[] sans trailing delimiter[], if any. If delimiter[] is null, removes trailing CR, LF, or CRLF, if any.

C1[] chompPrefix(C1, C2)(C1[] longer, C2[] shorter);
  If longer.startsWith(shorter), returns longer[shorter.length .. $]. Otherwise, returns longer.

string chop(string s);
  Returns s[] sans trailing character, if there is one. If last two characters are CR-LF, then both are removed.

string ljustify(string s, int width);
string rjustify(string s, int width);
string center(string s, int width);
  Left justify, right justify, or center string s[] in field width chars wide.

string zfill(string s, int width);
  Same as rjustify(), but fill with '0's.

string replace(string s, string from, string to);
  Replace occurrences of from[] with to[] in s[].

string replaceSlice(string s, in string slice, in string replacement);
  Return a string that is s[] with slice[] replaced by replacement[].

string insert(string s, size_t index, string sub);
  Insert sub[] into s[] at location index.

size_t count(string s, string sub);
  Count up all instances of sub[] in s[].

string expandtabs(string str, int tabsize = 8);
  Replace tabs with the appropriate number of spaces. tabsize is the distance between tab stops.

string entab(string s, int tabsize = 8);
  Replace spaces in string s with the optimal number of tabs. Trailing spaces or tabs in a line are removed.

  Parameters:

  string s | String to convert.
  int tabsize | Tab columns are tabsize spaces apart. tabsize defaults to 8.

string maketrans(in string from, in string to);
  Construct translation table for translate().

  BUG:
  only works with ASCII

string translate(string s, in string transtab, in string delchars);
  Translate characters in s[] using table created by maketrans(). Delete chars in delchars[].

  BUG:
  only works with ASCII

string format(...);
  Format arguments into a string.

char[] sformat(char[] s,...);
  Format arguments into string s which must be large enough to hold the result. Throws RangeError if it is not.

  Returns:
  s

bool inPattern(dchar c, in string pattern);
  See if character c is in the pattern.

  Patterns:
  A pattern is an array of characters much like a character class in regular expressions. A sequence of characters can be given, such as "abcde". The '-' can represent a range of characters, as "a-e" represents the same pattern as "abcde". "a-fA-F0-9" represents all the hex characters. If the first character of a pattern is '^', then the pattern is negated, i.e. "^0-9" means any character except a digit. The functions inPattern, countchars, removeschars, and squeeze use patterns.

  Note:
  In the future, the pattern syntax may be improved to be more like regular expression character classes.

int inPattern(dchar c, immutable(char)[][] patterns);
  See if character c is in the intersection of the patterns.

size_t countchars(string s, string pattern);
  Count characters in s that match pattern.

string removechars(string s, in string pattern);
  Return string that is s with all characters removed that match pattern.

string squeeze(string s, string pattern = null);
  Return string where sequences of a character in s[] from pattern[] are replaced with a single instance of that character. If pattern is null, it defaults to all characters.

S1 munch(S1, S2)(ref S1 s, S2 pattern);
  Finds the position pos of the first character in s that does not match pattern (in the terminology used by inPattern). Updates s = s[pos..$]. Returns the slice from the beginning of the original (before update) string up to, and excluding, pos.

  Example:

      string s = "123abc";
      string t = munch(s, "0123456789");
      assert(t == "123" && s == "abc");
      t = munch(s, "0123456789");
      assert(t == "" && s == "abc");

  The munch function is mostly convenient for skipping certain category of characters (e.g. whitespace) when parsing strings. (In such cases, the return value is not used.)

string succ(string 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.

string tr(string str, string from, string to, string modifiers = null);
  Replaces characters in str[] that are in from[] with corresponding characters in to[] and returns the resulting string.

  Parameters:

  string modifiers | a string of modifier characters

  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 modifier d is present, then the number of characters in to[] may be only 0 or 1.

  If modifier d is not present and to[] is null, then to[] is taken to be the same as from[].

  If 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, for example a-d is synonymous with abcd. Neither accept a leading ^ as meaning the complement of the string (use the c modifier for that).

final bool isNumeric(string s, in bool bAllowSep = false);
  [in] string s can be formatted in the following ways:

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

  Examples:
  123, 123UL, 123L, +123U, -123L

  Floating-Point Number: (for 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]

  Examples:
  +123., -123.01, 123.3e-10f, 123.3e-10fi, 123.3e-10L

  (for 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]

  Examples:
  nan, -123e-1+456.9e-10Li, +123e+10+456i, 123+456

  [in] bool bAllowSep False by default, but when set to true it 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 toInt(), toFloat(), 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.

bool isNumeric(...);
  Allow any object as a parameter

bool isNumeric(TypeInfo[] _arguments, va_list _argptr);
  Check only the first parameter, all others will be ignored.

char[] soundex(string string, char[] buffer = null);
  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:

  string string | 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:
  Wikipedia, The Soundex Indexing System

  BUGS:
  Only works well with English names. There are other arguably better Soundex algorithms, but this one is the standard one.

immutable(char)[][immutable(char)[]] abbrev(immutable(char)[][] 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 autocomplete the string once sufficient characters have been entered that uniquely identify it.

  Example:

       import std.stdio;
       import std.string;

       void main()
       {
          static string[] list = [ "food", "foxy" ];

          auto abbrevs = std.string.abbrev(list);

          foreach (key, value; abbrevs)
          {
             writefln("%s => %s", key, value);
          }
       }

  produces the output:

       fox => foxy
       food => food
       foxy => foxy
       foo => food

size_t column(string str, int tabsize = 8);
  Compute column number after string if string starts in the leftmost column, which is numbered starting from 0.

string wrap(string s, int columns = 80, string firstindent = null, string indent = null, int tabsize = 8);
  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:

  string s | text string to be wrapped
  int columns | maximum number of columns in the paragraph
  string firstindent | string used to indent first line of the paragraph
  string indent | string to use to indent following lines of the paragraph
  int tabsize | column spacing of tabs

  Returns:
  The resulting paragraph.

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