1Stdlib.String(3) OCaml library Stdlib.String(3)
2
6 Stdlib.String - no description
7
9 Module Stdlib.String
10
12 Module String
13 : (module Stdlib__string)
14 Strings
24 type t = string
25 The type for strings.
28 val make : int -> char -> string
32 make n c is a string of length n with each index holding the character
35 c .
36 Raises Invalid_argument if n < 0 or n > Sys.max_string_length .
39 val init : int -> (int -> char) -> string
43 init n f is a string of length n with index i holding the character f i
46 (called in increasing index order).
47 Since 4.02.0
50 Raises Invalid_argument if n < 0 or n > Sys.max_string_length .
53 val length : string -> int
57 length s is the length (number of bytes/characters) of s .
60 val get : string -> int -> char
64 get s i is the character at index i in s . This is the same as writing
67 s.[i] .
68 Raises Invalid_argument if i not an index of s .
71 Concatenating
76 Note. The (^) binary operator concatenates two strings.
77 val concat : string -> string list -> string
79 concat sep ss concatenates the list of strings ss , inserting the sepa‐
82 rator string sep between each.
83 Raises Invalid_argument if the result is longer than
86 Sys.max_string_length bytes.
87 Predicates and comparisons
92 val equal : t -> t -> bool
93 equal s0 s1 is true if and only if s0 and s1 are character-wise equal.
96 Since 4.03.0 (4.05.0 in StringLabels)
99 val compare : t -> t -> int
103 compare s0 s1 sorts s0 and s1 in lexicographical order. compare be‐
106 haves like compare on strings but may be more efficient.
107 val contains_from : string -> int -> char -> bool
111 contains_from s start c is true if and only if c appears in s after po‐
114 sition start .
115 Raises Invalid_argument if start is not a valid position in s .
118 val rcontains_from : string -> int -> char -> bool
122 rcontains_from s stop c is true if and only if c appears in s before
125 position stop+1 .
126 Raises Invalid_argument if stop < 0 or stop+1 is not a valid position
129 in s .
130 val contains : string -> char -> bool
134 contains s c is String.contains_from s 0 c .
137 Extracting substrings
142 val sub : string -> int -> int -> string
143 sub s pos len is a string of length len , containing the substring of s
146 that starts at position pos and has length len .
147 Raises Invalid_argument if pos and len do not designate a valid sub‐
150 string of s .
151 val split_on_char : char -> string -> string list
155 split_on_char sep s is the list of all (possibly empty) substrings of s
158 that are delimited by the character sep .
159 The function's result is specified by the following invariants:
161 -The list is not empty.
163 -Concatenating its elements using sep as a separator returns a string
165 equal to the input ( concat (make 1 sep)
166 (split_on_char sep s) = s ).
167 -No string in the result contains the sep character.
169 Since 4.04.0 (4.05.0 in StringLabels)
173 Transforming
178 val map : (char -> char) -> string -> string
179 map f s is the string resulting from applying f to all the characters
182 of s in increasing order.
183 Since 4.00.0
186 val mapi : (int -> char -> char) -> string -> string
190 mapi f s is like String.map but the index of the character is also
193 passed to f .
194 Since 4.02.0
197 val trim : string -> string
201 trim s is s without leading and trailing whitespace. Whitespace charac‐
204 ters are: ' ' , '\x0C' (form feed), '\n' , '\r' , and '\t' .
205 Since 4.00.0
208 val escaped : string -> string
212 escaped s is s with special characters represented by escape sequences,
215 following the lexical conventions of OCaml.
216 All characters outside the US-ASCII printable range [0x20;0x7E] are es‐
218 caped, as well as backslash (0x2F) and double-quote (0x22).
219 The function Scanf.unescaped is a left inverse of escaped , i.e.
221 Scanf.unescaped (escaped s) = s for any string s (unless escaped s
222 fails).
223 Raises Invalid_argument if the result is longer than
226 Sys.max_string_length bytes.
227 val uppercase_ascii : string -> string
231 uppercase_ascii s is s with all lowercase letters translated to upper‐
234 case, using the US-ASCII character set.
235 Since 4.03.0 (4.05.0 in StringLabels)
238 val lowercase_ascii : string -> string
242 lowercase_ascii s is s with all uppercase letters translated to lower‐
245 case, using the US-ASCII character set.
246 Since 4.03.0 (4.05.0 in StringLabels)
249 val capitalize_ascii : string -> string
253 capitalize_ascii s is s with the first character set to uppercase, us‐
256 ing the US-ASCII character set.
257 Since 4.03.0 (4.05.0 in StringLabels)
260 val uncapitalize_ascii : string -> string
264 uncapitalize_ascii s is s with the first character set to lowercase,
267 using the US-ASCII character set.
268 Since 4.03.0 (4.05.0 in StringLabels)
271 Traversing
276 val iter : (char -> unit) -> string -> unit
277 iter f s applies function f in turn to all the characters of s . It is
280 equivalent to f s.[0]; f s.[1]; ...; f s.[length s - 1]; () .
281 val iteri : (int -> char -> unit) -> string -> unit
285 iteri is like String.iter , but the function is also given the corre‐
288 sponding character index.
289 Since 4.00.0
292 Searching
297 val index_from : string -> int -> char -> int
298 index_from s i c is the index of the first occurrence of c in s after
301 position i .
302 Raises Not_found if c does not occur in s after position i .
305 Raises Invalid_argument if i is not a valid position in s .
308 val index_from_opt : string -> int -> char -> int option
312 index_from_opt s i c is the index of the first occurrence of c in s af‐
315 ter position i (if any).
316 Since 4.05
319 Raises Invalid_argument if i is not a valid position in s .
322 val rindex_from : string -> int -> char -> int
326 rindex_from s i c is the index of the last occurrence of c in s before
329 position i+1 .
330 Raises Not_found if c does not occur in s before position i+1 .
333 Raises Invalid_argument if i+1 is not a valid position in s .
336 val rindex_from_opt : string -> int -> char -> int option
340 rindex_from_opt s i c is the index of the last occurrence of c in s be‐
343 fore position i+1 (if any).
344 Since 4.05
347 Raises Invalid_argument if i+1 is not a valid position in s .
350 val index : string -> char -> int
354 index s c is String.index_from s 0 c .
357 val index_opt : string -> char -> int option
361 index_opt s c is String.index_from_opt s 0 c .
364 Since 4.05
367 val rindex : string -> char -> int
371 rindex s c is String.rindex_from s (length s - 1) c .
374 val rindex_opt : string -> char -> int option
378 rindex_opt s c is String.rindex_from_opt s (length s - 1) c .
381 Since 4.05
384 Converting
389 val to_seq : t -> char Seq.t
390 to_seq s is a sequence made of the string's characters in increasing
393 order. In "unsafe-string" mode, modifications of the string during it‐
394 eration will be reflected in the iterator.
395 Since 4.07
398 val to_seqi : t -> (int * char) Seq.t
402 to_seqi s is like String.to_seq but also tuples the corresponding in‐
405 dex.
406 Since 4.07
409 val of_seq : char Seq.t -> t
413 of_seq s is a string made of the sequence's characters.
416 Since 4.07
419 Deprecated functions
424 val create : int -> bytes
425 Deprecated. This is a deprecated alias of Bytes.create / BytesLa‐
427 bels.create .
428 create n returns a fresh byte sequence of length n . The sequence is
432 uninitialized and contains arbitrary bytes.
433 Raises Invalid_argument if n < 0 or n > Sys.max_string_length .
436 val set : bytes -> int -> char -> unit
440 Deprecated. This is a deprecated alias of Bytes.set / BytesLabels.set
442 .
443 set s n c modifies byte sequence s in place, replacing the byte at in‐
447 dex n with c . You can also write s.[n] <- c instead of set s n c .
448 Raises Invalid_argument if n is not a valid index in s .
451 val blit : string -> int -> bytes -> int -> int -> unit
455 blit src src_pos dst dst_pos len copies len bytes from the string src ,
458 starting at index src_pos , to byte sequence dst , starting at charac‐
459 ter number dst_pos .
460 Raises Invalid_argument if src_pos and len do not designate a valid
463 range of src , or if dst_pos and len do not designate a valid range of
464 dst .
465 val copy : string -> string
469 Deprecated. Because strings are immutable, it doesn't make much sense
471 to make identical copies of them.
472 Return a copy of the given string.
475 val fill : bytes -> int -> int -> char -> unit
479 Deprecated. This is a deprecated alias of Bytes.fill / BytesLa‐
481 bels.fill .
482 fill s pos len c modifies byte sequence s in place, replacing len bytes
486 by c , starting at pos .
487 Raises Invalid_argument if pos and len do not designate a valid sub‐
490 string of s .
491 val uppercase : string -> string
495 Deprecated. Functions operating on Latin-1 character set are depre‐
497 cated.
498 Return a copy of the argument, with all lowercase letters translated to
501 uppercase, including accented letters of the ISO Latin-1 (8859-1) char‐
502 acter set.
503 val lowercase : string -> string
507 Deprecated. Functions operating on Latin-1 character set are depre‐
509 cated.
510 Return a copy of the argument, with all uppercase letters translated to
513 lowercase, including accented letters of the ISO Latin-1 (8859-1) char‐
514 acter set.
515 val capitalize : string -> string
519 Deprecated. Functions operating on Latin-1 character set are depre‐
521 cated.
522 Return a copy of the argument, with the first character set to upper‐
525 case, using the ISO Latin-1 (8859-1) character set..
526 val uncapitalize : string -> string
530 Deprecated. Functions operating on Latin-1 character set are depre‐
532 cated.
533 Return a copy of the argument, with the first character set to lower‐
536 case, using the ISO Latin-1 (8859-1) character set.
537OCamldoc 2021-07-22 Stdlib.String(3)