string(3erl)
NAME
string - String processing functions.
DESCRIPTION
This module provides functions for string processing.
EXPORTS
centre(String, Number) -> Centered
centre(String, Number, Character) -> Centered
Types:
String = Centered = string()
Number = integer() >= 0
Character = char()
Returns a string, where String is centered in the string and
surrounded by blanks or Character. The resulting string has
length Number.
chars(Character, Number) -> String
chars(Character, Number, Tail) -> String
Types:
Character = char()
Number = integer() >= 0
Tail = String = string()
Returns a string consisting of Number characters Character.
Optionally, the string can end with string Tail.
chr(String, Character) -> Index
Types:
String = string()
Character = char()
Index = integer() >= 0
Returns the index of the first occurrence of Character in
String. Returns 0 if Character does not occur.
concat(String1, String2) -> String3
Types:
String1 = String2 = String3 = string()
Concatenates String1 and String2 to form a new string String3,
which is returned.
copies(String, Number) -> Copies
Types:
String = Copies = string()
Number = integer() >= 0
Returns a string containing String repeated Number times.
cspan(String, Chars) -> Length
Types:
String = Chars = string()
Length = integer() >= 0
Returns the length of the maximum initial segment of String,
which consists entirely of characters not from Chars.
Example:
> string:cspan("\t abcdef", " \t").
0
equal(String1, String2) -> boolean()
Types:
String1 = String2 = string()
Returns true if String1 and String2 are equal, otherwise false.
join(StringList, Separator) -> String
Types:
StringList = [string()]
Separator = String = string()
Returns a string with the elements of StringList separated by
the string in Separator.
Example:
> join(["one", "two", "three"], ", ").
"one, two, three"
left(String, Number) -> Left
left(String, Number, Character) -> Left
Types:
String = Left = string()
Number = integer() >= 0
Character = char()
Returns String with the length adjusted in accordance with
Number. The left margin is fixed. If length(String) < Number,
then String is padded with blanks or Characters.
Example:
> string:left("Hello",10,$.).
"Hello....."
len(String) -> Length
Types:
String = string()
Length = integer() >= 0
Returns the number of characters in String.
rchr(String, Character) -> Index
Types:
String = string()
Character = char()
Index = integer() >= 0
Returns the index of the last occurrence of Character in String.
Returns 0 if Character does not occur.
right(String, Number) -> Right
right(String, Number, Character) -> Right
Types:
String = Right = string()
Number = integer() >= 0
Character = char()
Returns String with the length adjusted in accordance with
Number. The right margin is fixed. If the length of (String) <
Number, then String is padded with blanks or Characters.
Example:
> string:right("Hello", 10, $.).
".....Hello"
rstr(String, SubString) -> Index
Types:
String = SubString = string()
Index = integer() >= 0
Returns the position where the last occurrence of SubString
begins in String. Returns 0 if SubString does not exist in
String.
Example:
> string:rstr(" Hello Hello World World ", "Hello World").
8
span(String, Chars) -> Length
Types:
String = Chars = string()
Length = integer() >= 0
Returns the length of the maximum initial segment of String,
which consists entirely of characters from Chars.
Example:
> string:span("\t abcdef", " \t").
5
str(String, SubString) -> Index
Types:
String = SubString = string()
Index = integer() >= 0
Returns the position where the first occurrence of SubString
begins in String. Returns 0 if SubString does not exist in
String.
Example:
> string:str(" Hello Hello World World ", "Hello World").
8
strip(String :: string()) -> string()
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, 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, $.).
"Hello"
sub_string(String, Start) -> SubString
sub_string(String, Start, Stop) -> SubString
Types:
String = SubString = string()
Start = Stop = integer() >= 1
Returns a substring of String, starting at position Start to the
end of the string, or to and including position Stop.
Example:
sub_string("Hello World", 4, 8).
"lo Wo"
substr(String, Start) -> SubString
substr(String, Start, Length) -> SubString
Types:
String = SubString = string()
Start = integer() >= 1
Length = integer() >= 0
Returns a substring of String, starting at position Start, and
ending at the end of the string or at length Length.
Example:
> substr("Hello World", 4, 5).
"lo Wo"
sub_word(String, Number) -> Word
sub_word(String, Number, Character) -> Word
Types:
String = Word = string()
Number = integer()
Character = char()
Returns the word in position Number of String. Words are
separated by blanks or Characters.
Example:
> string:sub_word(" Hello old boy !",3,$o).
"ld b"
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 are 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}
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 are 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
Types:
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
Types:
String = SeparatorList = string()
Tokens = [Token :: nonempty_string()]
Returns a list of tokens in String, separated by the characters
in SeparatorList.
Example:
> tokens("abc defxxghix jkl", "x ").
["abc", "def", "ghi", "jkl"]
Notice that, as shown in this example, two or more adjacent
separator characters in String are treated as one. That is,
there are no empty strings in the resulting list of tokens.
words(String) -> Count
words(String, Character) -> Count
Types:
String = string()
Character = char()
Count = integer() >= 1
Returns the number of words in String, separated by blanks or
Character.
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.
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