string

19962009 Ericsson AB. All Rights Reserved. The contents of this file are subject to the Erlang Public License, Version 1.1, (the "License"); you may not use this file except in compliance with the License. You should have received a copy of the Erlang Public License along with this software. If not, it can be retrieved online at http://www.erlang.org/. Software distributed under the License is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for the specific language governing rights and limitations under the License. string Robert Virding Bjarne Dacker 1 Bjarne Däcker 96-09-28 A string.sgml

string String Processing Functions

This module contains functions for string processing.

len(String) -> Length Return the length of a string String = string() Length = integer()

Returns the number of characters in the string.

equal(String1, String2) -> bool() Test string equality String1 = String2 = string()

Tests whether two strings are equal. Returns true if they are, otherwise false.

concat(String1, String2) -> String3 Concatenate two strings String1 = String2 = String3 = string()

Concatenates two strings to form a new string. Returns the new string.

chr(String, Character) -> Index rchr(String, Character) -> Index Return the index of the first/last occurrence ofCharacterin String String = string() Character = char() Index = integer()

Returns the index of the first/last occurrence of Character in String. 0 is returned if Character does not occur.

str(String, SubString) -> Index rstr(String, SubString) -> Index Find the index of a substring String = SubString = string() Index = integer()

Returns the position where the first/last occurrence of SubString begins in String. 0 is returned if SubString does not exist in String. For example:


> string:str(" Hello Hello World World ", "Hello World").
8

span(String, Chars) -> Length cspan(String, Chars) -> Length Span characters at start of string String = Chars = string() Length = integer()

Returns the length of the maximum initial segment of String, which consists entirely of characters from (not from) Chars.

For example:


> string:span("\t    abcdef", " \t").
5
> string:cspan("\t    abcdef", " \t").
0

substr(String, Start) -> SubString substr(String, Start, Length) -> Substring Return a substring of String String = SubString = string() Start = Length = integer()

Returns a substring of String, starting at the position Start, and ending at the end of the string or at length Length.

For example:


> substr("Hello World", 4, 5).
"lo Wo"

tokens(String, SeparatorList) -> Tokens Split string into tokens String = SeparatorList = string() Tokens = [string()]

Returns a list of tokens in String, separated by the characters in SeparatorList.

For example:


> tokens("abc defxxghix jkl", "x ").
["abc", "def", "ghi", "jkl"]

join(StringList, Separator) -> String Join a list of strings with separator StringList = [string()] Separator = string()

Returns a string with the elements of StringList separated by the string in Seperator.

For example:


> join(["one", "two", "three"], ", ").
"one, two, three"

chars(Character, Number) -> String chars(Character, Number, Tail) -> String Returns a string consisting of numbers of characters Character = char() Number = integer() String = string()

Returns a string consisting of Number of characters Character. Optionally, the string can end with the string Tail.

copies(String, Number) -> Copies Copy a string String = Copies = string() Number = integer()

Returns a string containing String repeated Number times.

words(String) -> Count words(String, Character) -> Count Count blank separated words String = string() Character = char() Count = integer()

Returns the number of words in String, separated by blanks or Character.

For example:


> words(" Hello old boy!", $o).
4

sub_word(String, Number) -> Word sub_word(String, Number, Character) -> Word Extract subword String = Word = string() Character = char() Number = integer()

Returns the word in position Number of String. Words are separated by blanks or Characters.

For example:


> string:sub_word(" Hello old boy !",3,$o).
"ld b"

strip(String) -> Stripped strip(String, Direction) -> Stripped strip(String, Direction, Character) -> Stripped Strip leading or trailing characters String = Stripped = string() Direction = left | right | both Character = char()

Returns a string, where leading and/or trailing blanks or a number of Character have been removed. Direction can be left, right, or both and indicates from which direction blanks are to be removed. The function strip/1 is equivalent to strip(String, both).

For example:


> string:strip("...Hello.....", both, $.).
"Hello"

left(String, Number) -> Left left(String, Number, Character) -> Left Adjust left end of string String = Left = string() Character = char Number = integer()

Returns the String with the length adjusted in accordance with Number. The left margin is fixed. If the length(String) < Number, String is padded with blanks or Characters.

For example:


> string:left("Hello",10,$.).
"Hello....."

right(String, Number) -> Right right(String, Number, Character) -> Right Adjust right end of string String = Right = string() Character = char Number = integer()

Returns the String with the length adjusted in accordance with Number. The right margin is fixed. If the length of (String) < Number, String is padded with blanks or Characters.

For example:


> string:right("Hello", 10, $.).
".....Hello"

centre(String, Number) -> Centered centre(String, Number, Character) -> Centered Center a string String = Centered = string() Character = char Number = integer()

Returns a string, where String is centred in the string and surrounded by blanks or characters. The resulting string will have the length Number.

sub_string(String, Start) -> SubString sub_string(String, Start, Stop) -> SubString Extract a substring String = SubString = string() Start = Stop = integer()

Returns a substring of String, starting at the position Start to the end of the string, or to and including the Stop position.

For example:


sub_string("Hello World", 4, 8).
"lo Wo"

to_float(String) -> {Float,Rest} | {error,Reason} Returns a float whose text representation is the integers (ASCII values) in String. String = string() Float = float() Rest = string() Reason = no_float | not_a_list

Argument String is expected to start with a valid text represented float (the digits being ASCII values). Remaining characters in the string after the float are returned in Rest.

Example:


          > {F1,Fs} = string:to_float("1.0-1.0e-1"),
          > {F2,[]} = string:to_float(Fs),
          > F1+F2.
          0.9
          > string:to_float("3/2=1.5").
          {error,no_float}
          > string:to_float("-1.5eX").
          {-1.5,"eX"}

to_integer(String) -> {Int,Rest} | {error,Reason} Returns an integer whose text representation is the integers (ASCII values) in String. String = string() Int = integer() Rest = string() Reason = no_integer | not_a_list

Argument String is expected to start with a valid text represented integer (the digits being ASCII values). Remaining characters in the string after the integer are returned in Rest.

Example:


          > {I1,Is} = string:to_integer("33+22"),
          > {I2,[]} = string:to_integer(Is),
          > I1-I2.
          11
          > string:to_integer("0.5").
          {0,".5"}
          > string:to_integer("x=2").
          {error,no_integer}

to_lower(String) -> Result to_lower(Char) -> CharResult to_upper(String) -> Result to_upper(Char) -> CharResult Convert case of string (ISO/IEC 8859-1) String = Result = string() Char = CharResult = integer()

The given string or character is case-converted. Note that the supported character set is ISO/IEC 8859-1 (a.k.a. Latin 1), all values outside this set is unchanged

Notes

Some of the general string functions may seem to overlap each other. The reason for this is that this string package is the combination of two earlier packages and all the functions of both packages have been retained.

Any undocumented functions in string should not be used.