utf8.md

UTF8

• utf8
• startwith
• endswith
• iequals
• equals
• sub
• char
• len
• indexof
• lastindexof
• replace
• contains
• trim
• tolower
• toupper
• empty
• split
• join (table)
• join (...)

utf8

The utf8 library provides essential string manipulation functions for UTF8 encoded text.

local utf8 = require("utf8");

All functions can be used as global functions

print(utf8.replace("foo bar", "foo", "hello")); -- "hello bar"

For best performance with large strings, create a UTF8 string instance and re-use it when possible. Note the instance (str:) syntax!

local str = utf8.new("foo bar");
str:replace("foo", "hello");
print(str:raw()); -- "hello bar"

utf8.startswith( string, find )

Checks if string start with the text find.

print(utf8.startswith("foo bar", "foo")); -- true
print(utf8.startswith("foo bar", "bar")); -- false

utf8.endswith( string, find )

Checks if string ends with the text find.

print(utf8.endswith("foo bar", "foo")); -- false
print(utf8.endswith("foo bar", "bar")); -- true

utf8.iequals( a, b )

Performs a case-insensitive equality check.

print(utf8.iequals("foo", "FOO")); -- true
print(utf8.iequals("foo", "foo")); -- true

utf8.equals( a, b )

Performs a case-sensitive equality check.

print(utf8.equals("foo", "FOO")); -- false
print(utf8.equals("foo", "foo")); -- true

utf8.sub( string, start, [length] )

Gets a part of a string from the start position to the end of the string or if length is set to the set length.

print(utf8.sub("This is a text string", 2, 5);  -- "his i"
print(utf8.sub("This is a text string", 2));    -- "his is a text string"

utf8.char( string, index )

Returns the character at a specific index in the string

print(utf8.char("This is a text string", 2)); -- 'i'

utf8.len( string )

Returns the length of a string.

print(utf8.len("This is a text string")); -- 21

utf8.indexof( string, find )

Returns the first index of find in the string.

print(utf8.indexof("This is a text string", "text")); -- 11

utf8.lastindexof( string, find )

Returns the last index of find in the string.

print(utf8.lastindexof("This is a text string", "t"));	-- 17

utf8.replace( string, old, new )

Replaces the string old with the string new in the string.

print(utf8.replace("foo bar", "foo", "hello")); -- "hello bar"

utf8.contains( string, find )

Returns true if string contains the string find.

print(utf8.contains("foo bar", "bar"));	-- true
print(utf8.contains("foo bar", "xyz"));	-- false

utf8.trim( string )

Removes spaces from the start and end of the string.

print(utf8.trim("   foo   "));	-- "foo"

utf8.tolower( string )

Returns a transformed version of the string where all letters are in lower-case

print(utf8.tolower("FOO"));	-- "foo"

utf8.toupper( string )

Returns a transformed version of the string where all letters are in upper-case

print(utf8.toupper("foo"));	-- "FOO"

utf8.empty( string )

Checkes if the string is empty.

print(utf8.empty("foo")); 	-- false
print(utf8.empty("")); 		-- true
print(utf8.empty(" "));		-- false

utf8.split( string, delim )

Splits the subject string using the specified delim.

print(utf8.split("foo bar hello world", " ")); -- { "foo", "bar", "hello", "world" }

utf8.join( delim, table )

Joins the items in table using delim.

local items = { "foo", "bar" };
print(utf8.join(" ", items)); -- "foo bar";

utf8.join( delim, part1, part2, ... )

Joins all parts using delim.

print(utf8.join(" ", "foo", "bar")); -- "foo bar";