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This module contains functions for string processing.
Types:
String = string()
Length = integer()
Returns the number of characters in the string.
equal(String1, String2) -> bool()
Types:
String1 = String2 = string()
Tests whether two strings are equal. Returns true if
they are, otherwise false.
concat(String1, String2) -> String3
Types:
String1 = String2 = String3 = string()
Concatenates two strings to form a new string. Returns the new string.
chr(String, Character) -> Index
rchr(String, Character) -> Index
Types:
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
Types:
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
Types:
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
Types:
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
Types:
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"]
chars(Character, Number) -> String
chars(Character, Number, Tail) -> String
Types:
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
Types:
String = Copies = string()
Number = integer()
Returns a string containing String repeated
Number times.
words(String) -> Count
words(String, Character) -> Count
Types:
String = string()
Character = char()
Count = integer()
Returns the number of words in String, separated by
blanks or Character.
For example:
> words(" Hello old boy!", $o).
4
sub_word(String, Number) -> Word
sub_word(String, Number, Character) -> Word
Types:
String = Word = string()
Character = char()
Number = integer()
Returns the word in position Number of String.
Words are separated by blanks or Characters.
For example:
> string:sub_word(" Hello old boy !",3,$o).
"ld b"
strip(String) -> Stripped
strip(String, Direction) -> Stripped
strip(String, Direction, Character) -> Stripped
Types:
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, $.).
"Hello"
left(String, Number) -> Left
left(String, Number, Character) -> Left
Types:
String = Left = string()
Character = char
Number = integer()
Returns the String with the length adjusted in
accordance with Number. The left margin is
fixed. If the length(String) < Number,
String is padded with blanks or Characters.
For example:
> string:left("Hello",10,$.).
"Hello....."
right(String, Number) -> Right
right(String, Number, Character) -> Right
Types:
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
Types:
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
Types:
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}
Types:
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.
0.900000
> string:to_float("3/2=1.5").
{error,no_float}
> string:to_float("-1.5eX").
{-1.50000,"eX"}
to_integer(String) -> {Int,Rest} | {error,Reason}
Types:
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}
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.
The regular expression functions have been moved to their own
module regexp (see regexp(3)).
The old entry points still
exist for backwards compatibility, but will be removed in a
future release so that users are encouraged to use the module
regexp.
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Any undocumented functions in |