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 String is centered in the string and surrounded by blanks or Character. The resulting string has length Number.

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 Number characters Character. Optionally, the string can end with string Tail.

chr(String, Character) -> Index

  • 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

  • String1 = String2 = String3 = string()

Concatenates String1 and String2 to form a new string String3, which is returned.

copies(String, Number) -> Copies

  • String = Copies = string()
  • Number = integer() >= 0

Returns a string containing String repeated Number times.

cspan(String, Chars) -> Length

  • 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()

  • String1 = String2 = string()

Returns true if String1 and String2 are equal, otherwise false.

join(StringList, Separator) -> String

  • 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

  • String = Left = string()
  • Number = integer() >= 0

left(String, Number, Character) -> Left

  • 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

  • String = string()
  • Length = integer() >= 0

Returns the number of characters in String.

rchr(String, Character) -> Index

  • 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

  • String = Right = string()
  • Number = integer() >= 0

right(String, Number, Character) -> Right

  • 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

  • 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

  • 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

  • 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

  • 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 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

  • String = SubString = string()
  • Start = integer() >= 1

sub_string(String, Start, Stop) -> SubString

  • 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

  • String = SubString = string()
  • Start = integer() >= 1

substr(String, Start, Length) -> SubString

  • 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

  • String = Word = string()
  • Number = integer()

sub_word(String, Number, Character) -> Word

  • 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}

  • 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}

  • 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

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 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

  • String = string()
  • Count = integer() >= 1

words(String, Character) -> Count

  • 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.