string
String processing functions.
This module provides functions for string processing.
Functions
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 centered in the
string and surrounded by blanks or
.
The resulting string has length
.
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
characters
. Optionally, the string can end with
string
.
chr(String, Character) -> Index
String = string()
Character = char()
Index = integer() >= 0
Returns the index of the first occurrence of
in
. Returns
0
if
does not occur.
concat(String1, String2) -> String3
String1 = String2 = String3 = string()
Concatenates
and
to form a new string
, which is returned.
copies(String, Number) -> Copies
String = Copies = string()
Number = integer() >= 0
Returns a string containing
repeated
times.
cspan(String, Chars) -> Length
String = Chars = string()
Length = integer() >= 0
Returns the length of the maximum initial segment of
, which consists entirely of characters
not from
.
Example:
> string:cspan("\t abcdef", " \t"). 0
equal(String1, String2) -> boolean()
String1 = String2 = string()
Returns true
if
and
are equal, otherwise false
.
join(StringList, Separator) -> String
StringList = [string()]
Separator = String = string()
Returns a string with the elements of
separated by the string in
.
Example:
> join(["one", "two", "three"], ", "). "one, two, three"
left(String, Number) -> Left
String = Left = string()
Number = integer() >= 0
left(String, Number, Character) -> Left
String = Left = string()
Number = integer() >= 0
Character = char()
Returns
with the length adjusted in
accordance with
. The left margin is
fixed. If length(
<
, then
is padded
with blanks or
s.
Example:
> string:left("Hello",10,$.). "Hello....."
len(String) -> Length
String = string()
Length = integer() >= 0
Returns the number of characters in
.
rchr(String, Character) -> Index
String = string()
Character = char()
Index = integer() >= 0
Returns the index of the last occurrence of
in
. Returns
0
if
does not occur.
right(String, Number) -> Right
String = Right = string()
Number = integer() >= 0
right(String, Number, Character) -> Right
String = Right = string()
Number = integer() >= 0
Character = char()
Returns
with the length adjusted in
accordance with
. The right margin is
fixed. If the length of (
<
, then
is padded
with blanks or
s.
Example:
> string:right("Hello", 10, $.). ".....Hello"
rstr(String, SubString) -> Index
String = SubString = string()
Index = integer() >= 0
Returns the position where the last occurrence of
begins in
.
Returns 0
if
does not exist in
.
Example:
> string:rstr(" Hello Hello World World ", "Hello World"). 8
span(String, Chars) -> Length
String = Chars = string()
Length = integer() >= 0
Returns the length of the maximum initial segment of
, which consists entirely of characters
from
.
Example:
> string:span("\t abcdef", " \t"). 5
str(String, SubString) -> Index
String = SubString = string()
Index = integer() >= 0
Returns the position where the first occurrence of
begins in
.
Returns 0
if
does not exist in
.
Example:
> string:str(" Hello Hello World World ", "Hello World"). 8
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.
, which can be left
, right
,
or both
, indicates from which direction blanks are to be
removed. strip/1
is equivalent to
strip(String, both)
.
Example:
> string:strip("...Hello.....", both, $.). "Hello"
sub_string(String, Start) -> SubString
String = SubString = string()
Start = integer() >= 1
sub_string(String, Start, Stop) -> SubString
String = SubString = string()
Start = Stop = integer() >= 1
Returns a substring of
, starting at
position
to the end of the string, or to
and including position
.
Example:
sub_string("Hello World", 4, 8). "lo Wo"
substr(String, Start) -> SubString
String = SubString = string()
Start = integer() >= 1
substr(String, Start, Length) -> SubString
String = SubString = string()
Start = integer() >= 1
Length = integer() >= 0
Returns a substring of
, starting at
position
, and ending at the end of the
string or at length
.
Example:
> substr("Hello World", 4, 5). "lo Wo"
sub_word(String, Number) -> Word
String = Word = string()
Number = integer()
sub_word(String, Number, Character) -> Word
String = Word = string()
Number = integer()
Character = char()
Returns the word in position
of
. Words are separated by blanks or
s.
Example:
> string:sub_word(" Hello old boy !",3,$o). "ld b"
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 are 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 are 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 specified string or character is case-converted. Notice that the supported character set is ISO/IEC 8859-1 (also called Latin 1); all values outside this set are unchanged
tokens(String, SeparatorList) -> Tokens
String = SeparatorList = string()
Tokens = [Token :: nonempty_string()]
Returns a list of tokens in
, separated
by the characters in
.
Example:
> tokens("abc defxxghix jkl", "x "). ["abc", "def", "ghi", "jkl"]
Notice that, as shown in this example, two or more
adjacent separator characters in
are treated as one. That is, there are no empty
strings in the resulting list of tokens.
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
.
Example:
> words(" Hello old boy!", $o). 4
Notes
Some of the general string functions can seem to overlap each other. The reason is that this string package is the combination of two earlier packages and all functions of both packages have been retained.
Note!
Any undocumented functions in string
are not to be used.