string.char()

The string.char() function converts numeric ASCII (or Unicode) values into their corresponding characters. It is commonly used to construct strings programmatically, perform encoding tasks, or debug character-level data.

Syntax

string.char(value1, value2, ...)

Parameters

Name
value1, value2, ...
Type
number
Description
A sequence of numeric ASCII (or Unicode) values to be converted into characters. Each value must be a valid code point (e.g., between 0 and 255 for ASCII).

Return Value

The function returns:

A string constructed by converting the provided numeric values into their corresponding characters.

Examples

Example 1: Convert a single numeric value to a character

The function converts one ASCII value to its corresponding character.

Example 1

print(string.char(65)) 

-- Output: A

Example 2: Convert multiple numeric values into a string

The function combines multiple ASCII values into a string.

Example 2

print(string.char(72, 101, 108, 108, 111)) 

-- Output: Hello

Example 3: Use Unicode values

You can use numeric Unicode values for non-ASCII characters as long as they are valid code points.

Example 3

print(string.char(195, 169)) 

-- Output: é (Unicode for 'é')

Example 4: Combine with `string.byte()`

You can use string.char() to reverse the effect of string.byte().

Example 4

local byteValues = {string.byte("Lua", 1, 3)}
local reconstructed = string.char(table.unpack(byteValues))

print(reconstructed)

-- Output: Lua

Example 5: Constructing special characters

You can construct strings with special characters using their ASCII values.

Example 5

print(string.char(33, 36, 64)) 

-- Output: !$@

Example 6: Handling invalid values

Invalid numeric values result in an error. Ensure the values are within the valid range.

Example 6

-- print(string.char(300)) 
-- Error: bad argument #1 to 'char' (value out of range)

Use Cases

Decoding: Convert numeric representations of characters back into readable strings.
String Construction: Dynamically build strings programmatically.
Debugging: Analyze or reconstruct encoded string data.