string.len()

The string.len() function in Lua calculates and returns the number of characters in a given string, including spaces and special characters. It is a simple and efficient way to measure string length.

Syntax

string.len(s)

Parameters

Return Value

Returns a number representing the length of the string.

Examples

Example 1: Basic String Length

Determine the length of a simple string.

local text = "Hello, Lua!"

local length = string.len(text)

print(length)  -- Output: 11

Example 2: Length of an Empty String

The function returns 0 for an empty string.

local text = ""

local length = string.len(text)

print(length)  -- Output: 0

Example 3: String with Spaces and Special Characters

Spaces and special characters are included in the length calculation.

local text = "  Lua is fun!  "

local length = string.len(text)

print(length)  -- Output: 15

Example 4: Comparing Lengths

You can use string.len() to compare the lengths of different strings.

local string1 = "cat"
local string2 = "elephant"

if string.len(string1) < string.len(string2) then
  print(string1 .. " is shorter than " .. string2)
end

-- Output: cat is shorter than elephant

Use Cases

• Validation: Ensuring a string meets minimum or maximum length requirements.
• Trimming Logic: Checking if a string exceeds a certain length before truncating.
• Comparison: Determining which of two strings is longer.

See also

• string.sub(): Extracts substrings from a string, often used with string.len() to slice strings based on their length.
• string.rep(): Repeats a string multiple times, where the length of the result is easily calculated with string.len().