string
(stdlib)String Processing Functions
This module contains functions for string processing.
Functions
len(String) -> Length
String = string()
Length = integer() >= 0
Returns the number of characters in the string.
equal(String1, String2) -> boolean()
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
String = string()
Character = char()
Index = integer() >= 0
rchr(String, Character) -> Index
String = string()
Character = char()
Index = integer() >= 0
Returns the index of the first/last occurrence of
in
. 0
is returned if
does not
occur.
str(String, SubString) -> Index
String = SubString = string()
Index = integer() >= 0
rstr(String, SubString) -> Index
String = SubString = string()
Index = integer() >= 0
Returns the position where the first/last occurrence of
begins in
. 0
is returned if
does not exist in
.
For example:
> string:str(" Hello Hello World World ", "Hello World"). 8
span(String, Chars) -> Length
String = Chars = string()
Length = integer() >= 0
cspan(String, Chars) -> Length
String = Chars = string()
Length = integer() >= 0
Returns the length of the maximum initial segment of
, which consists entirely of characters from (not
from)
.
For example:
> string:span("\t abcdef", " \t"). 5 > string:cspan("\t abcdef", " \t"). 0
substr(String, Start) -> SubString
String = SubString = string()
Start = integer() >= 1
substr(String, Start, Length) -> SubString
String = SubString = string()
Start = integer() >= 1
Length = integer() >= 0
Returns a substring of
, starting at the
position
, and ending at the end of the string or
at length
.
For example:
> substr("Hello World", 4, 5). "lo Wo"
tokens(String, SeparatorList) -> Tokens
String = SeparatorList = string()
Tokens = [Token :: nonempty_string()]
Returns a list of tokens in
, separated by the
characters in
.
For example:
> tokens("abc defxxghix jkl", "x "). ["abc", "def", "ghi", "jkl"]
Note that, as shown in the example above, two or more
adjacent separator characters in
will be treated as one. That is, there will not be any empty
strings in the resulting list of tokens.
join(StringList, Separator) -> String
StringList = [string()]
Separator = String = string()
Returns a string with the elements of
separated by the string in
.
For example:
> join(["one", "two", "three"], ", "). "one, two, three"
chars(Character, Number) -> String
Character = char()
Number = integer() >= 0
String = string()
chars(Character, Number, Tail) -> String
Character = char()
Number = integer() >= 0
Tail = String = string()
Returns a string consisting of
of characters
. Optionally, the string can end with the
string
.
copies(String, Number) -> Copies
String = Copies = string()
Number = integer() >= 0
Returns a string containing
repeated
times.
words(String) -> Count
String = string()
Count = integer() >= 1
words(String, Character) -> Count
String = string()
Character = char()
Count = integer() >= 1
Returns the number of words in
, separated by
blanks or
.
For example:
> words(" Hello old boy!", $o). 4
sub_word(String, Number) -> Word
String = Word = string()
Number = integer()
sub_word(String, Number, Character) -> Word
String = Word = string()
Number = integer()
Character = char()
Returns the word in position
of
.
Words are separated by blanks or
s.
For example:
> string:sub_word(" Hello old boy !",3,$o). "ld b"
strip(String :: string()) -> string()
strip(String, Direction) -> Stripped
String = Stripped = string()
Direction = left | right | both
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
have been removed.
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, $.). "Hello"
left(String, Number) -> Left
String = Left = string()
Number = integer() >= 0
left(String, Number, Character) -> Left
String = Left = string()
Number = integer() >= 0
Character = char()
Returns the
with the length adjusted in
accordance with
. The left margin is
fixed. If the length(
<
,
is padded with blanks or
s.
For example:
> string:left("Hello",10,$.). "Hello....."
right(String, Number) -> Right
String = Right = string()
Number = integer() >= 0
right(String, Number, Character) -> Right
String = Right = string()
Number = integer() >= 0
Character = char()
Returns the
with the length adjusted in
accordance with
. The right margin is
fixed. If the length of (
<
,
is padded with blanks or
s.
For example:
> string:right("Hello", 10, $.). ".....Hello"
centre(String, Number) -> Centered
String = Centered = string()
Number = integer() >= 0
centre(String, Number, Character) -> Centered
String = Centered = string()
Number = integer() >= 0
Character = char()
Returns a string, where
is centred in the
string and surrounded by blanks or characters. The resulting
string will have the length
.
sub_string(String, Start) -> SubString
String = SubString = string()
Start = integer() >= 1
sub_string(String, Start, Stop) -> SubString
String = SubString = string()
Start = Stop = integer() >= 1
Returns a substring of
, starting at the
position
to the end of the string, or to and
including the
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
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
.
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
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
.
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
String = Result = io_lib:latin1_string()
Char = CharResult = char()
to_upper(String) -> Result
to_upper(Char) -> CharResult
String = Result = io_lib:latin1_string()
Char = CharResult = char()
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.