Converts String to a case-agnostic comparable string. Function casefold/1 is preferred over lowercase/1 when two strings are to be compared for equality. See also equal/4.

Example:

1> string:casefold("Ω and ẞ SHARP S").
"ω and ss sharp s"

Returns a string where any trailing \n or \r\n have been removed from String.

Example:

182> string:chomp(<<"\nHello\n\n">>).
<<"\nHello">>
183> string:chomp("\nHello\r\r\n").
"\nHello\r"

Returns true if String is the empty string, otherwise false.

Example:

1> string:is_empty("foo").
false
2> string:is_empty(["",<<>>]).
true

Returns the number of grapheme clusters in String.

Example:

1> string:length("ß↑e̊").
3
2> string:length(<<195,159,226,134,145,101,204,138>>).
3

Returns a list of lexemes in String, separated by the grapheme clusters in SeparatorList.

Notice that, as shown in this example, two or more adjacent separator graphemes clusters in String are treated as one. That is, there are no empty strings in the resulting list of lexemes. See also split/3 which returns empty strings.

Notice that [$\r,$\n] is one grapheme cluster.

Example:

1> string:lexemes("abc de̊fxxghix jkl\r\nfoo", "x e" ++ [[$\r,$\n]]).
["abc","de̊f","ghi","jkl","foo"]
2> string:lexemes(<<"abc de̊fxxghix jkl\r\nfoo"/utf8>>, "x e" ++ [$\r,$\n]).
[<<"abc">>,<<"de̊f"/utf8>>,<<"ghi">>,<<"jkl\r\nfoo">>]

Converts String to lowercase.

Notice that function casefold/1 should be used when converting a string to be tested for equality.

Example:

2> string:lowercase(string:uppercase("Michał")).
"michał"

Returns the first codepoint in String and the rest of String in the tail.

Example:

1> string:next_codepoint(unicode:characters_to_binary("e̊fg")).
[101|<<"̊fg"/utf8>>]

Returns the first grapheme cluster in String and the rest of String in the tail.

Example:

1> string:next_grapheme(unicode:characters_to_binary("e̊fg")).
["e̊"|<<"fg">>]

Returns lexeme number N in String, where lexemes are separated by the grapheme clusters in SeparatorList.

Example:

1> string:nth_lexeme("abc.de̊f.ghiejkl", 3, ".e").
"ghi"

If Prefix is the prefix of String, removes it and returns the remainder of String, otherwise returns nomatch.

Example:

1> string:prefix(<<"prefix of string">>, "pre").
<<"fix of string">>
2> string:prefix("pre", "prefix").
nomatch

Returns the reverse list of the grapheme clusters in String.

Example:

1> Reverse = string:reverse(unicode:characters_to_nfd_binary("ÅÄÖ")).
[[79,776],[65,776],[65,778]]
2> io:format("~ts~n",[Reverse]).
ÖÄÅ

Converts String to titlecase.

Example:

1> string:titlecase("ß is a SHARP s").
"Ss is a SHARP s"

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"}

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}

Converts String to a list of grapheme clusters.

Example:

1> string:to_graphemes("ß↑e̊").
[223,8593,[101,778]]
2> string:to_graphemes(<<"ß↑e̊"/utf8>>).
[223,8593,[101,778]]

Converts String to uppercase.

See also titlecase/1.

Example:

1> string:uppercase("Michał").
"MICHAŁ"

Returns the index of the first occurrence of Character in String. Returns 0 if Character does not occur.

This function is obsolete. Use find/2.

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

This function is obsolete. Use [String1, String2] as Data argument, and call unicode:characters_to_list/2 or unicode:characters_to_binary/2 to flatten the output.

Returns a string containing String repeated Number times.

This function is obsolete. Use lists:duplicate/2.

Returns the length of the maximum initial segment of String, which consists entirely of characters not from Chars.

This function is obsolete. Use take/3.

Example:

Returns a string with the elements of StringList separated by the string in Separator.

This function is obsolete. Use lists:join/2.

Example:

Returns the number of characters in String.

This function is obsolete. Use length/1.

Returns the index of the last occurrence of Character in String. Returns 0 if Character does not occur.

This function is obsolete. Use find/3.

Returns the position where the last occurrence of SubString begins in String. Returns 0 if SubString does not exist in String.

This function is obsolete. Use find/3.

Example:

Returns the length of the maximum initial segment of String, which consists entirely of characters from Chars.

This function is obsolete. Use take/2.

Example:

Returns the position where the first occurrence of SubString begins in String. Returns 0 if SubString does not exist in String.

This function is obsolete. Use find/2.

Example:

Returns a list of tokens in String, separated by the characters in SeparatorList.

Example:

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.

This function is obsolete. Use lexemes/2.