Utf8.charpos

Converts the UTF-8 codepoint position to byte-string position.

[[{{{image}}}|link=|]]	Note: Code point characters beyond the byte value range (0-127) require at least 2 bytes to represent the character

Syntax

int, int utf8.charpos ( string input [[, int charpos = 0 ], int offset = 1 ] )

Required Arguments

• input: A string character sequence

Optional Arguments

NOTE: When using optional arguments, you might need to supply all arguments before the one you wish to use. For more information on optional arguments, see optional arguments.

• charpos: An integer representing the beginning position (offset will be added/subtracted).
• offset: An integer representing the offset to charpos.

Returns

Returns the integer position as in a byte string and the integer code point at this position, nil otherwise.

Example

Click to collapse [-]

Server

This example takes the second codepoint character and shows the byte-string position and the code point character code.

local position, codepoint = utf8.charpos( "Привет", 2 )
print( position, codepoint )  -- 3, 1088

Click to collapse [-]

Client

This example extracts the first character by calculating the character length with the UTF8 functions and the inbuilt Lua function string.sub, which processes byte strings.

local input = "Привет мир" -- Hello World
local from = utf8.charpos( input, 1 ) -- 1
local to = utf8.charpos( input, 2 ) -- 3

local byteLength = to - from
outputConsole( byteLength ) -- 2

local character = string.sub( input, from, byteLength )
outputConsole( character ) -- П

See Also

• utf8.byte
• utf8.char
• utf8.charpos
• utf8.escape
• utf8.find
• utf8.fold
• utf8.gmatch
• utf8.gsub
• utf8.insert
• utf8.len
• utf8.lower
• utf8.match
• utf8.ncasecmp
• utf8.next
• utf8.remove
• utf8.reverse
• utf8.sub
• utf8.title
• utf8.upper
• utf8.width
• utf8.widthindex