string
String Processing Functions
This module contains functions for string processing.
Functions
len(String) -> Length
String = string()
Length = integer()
Returns the number of characters in the string.
equal(String1, String2) -> bool()
String1 = String2 = string()
Tests whether two strings are equal. Returns true
if
they are, otherwise false
.
concat(String1, String2) -> String3
String1 = String2 = String3 = string()
Concatenates two strings to form a new string. Returns the new string.
chr(String, Character) -> Index
rchr(String, Character) -> Index
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
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
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
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
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
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
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
String = Copies = string()
Number = integer()
Returns a string containing String
repeated
Number
times.
words(String) -> Count
words(String, Character) -> Count
String = string()
Character = char()
Count = integer()
Returns the number of words in String
, separated by
blanks or Character
.
For example:
> words(" Hello old boy!", $o). 4
sub_word(String, Number) -> Word
sub_word(String, Number, Character) -> Word
String = Word = string()
Character = char()
Number = integer()
Returns the word in position Number
of String
.
Words are separated by blanks or Character
s.
For example:
> string:sub_word(" Hello old boy !",3,$o). "ld b"
strip(String) -> Stripped
strip(String, Direction) -> Stripped
strip(String, Direction, Character) -> Stripped
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, $.). "Hello"
left(String, Number) -> Left
left(String, Number, Character) -> Left
String = Left = string()
Character = char
Number = integer()
Returns the String
with the length adjusted in
accordance with Number
. The left margin is
fixed. If the length(String)
< Number
,
String
is padded with blanks or Character
s.
For example:
> string:left("Hello",10,$.). "Hello....."
right(String, Number) -> Right
right(String, Number, Character) -> Right
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 Character
s.
For example:
> string:right("Hello", 10, $.). ".....Hello"
centre(String, Number) -> Centered
centre(String, Number, Character) -> Centered
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
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}
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}
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
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.
Note!
Any undocumented functions in string
should not be used.