Regex
The Regex library provides regular expression functionality for Lua, allowing pattern matching and string manipulation using regular expressions.
Regex.new(pattern)
Creates a new regex object with the given pattern.
Returns a regex object. If the pattern is invalid, the regex object will be created but marked as invalid (see Status method).
Regex.Escape(str)
Escapes special regex characters in a string.
Returns the escaped string.
Regex Object Methods
regex:Status()
Checks the validity of the regex pattern.
local regex = Regex.new("\\d+")
local valid, error = regex:Status()
if valid then
print("Regex is valid")
else
print("Regex is invalid: " .. error)
end
Returns two values: 1. A boolean indicating if the regex is valid 2. An error message string (empty if valid)
regex:Match(str)
Finds all matches of the regex pattern in the given string.
local regex = Regex.new("\\d+")
local matches = regex:Match("There are 123 apples and 456 oranges")
for i, match in ipairs(matches) do
print(i, match)
end
Returns a table of all matches found in the string.
regex:Replace(str, replacement)
Replaces the first occurrence of the regex pattern in the string with the replacement string.
local regex = Regex.new("\\d+")
local result = regex:Replace("There are 123 apples", "many")
-- result is now "There are many apples"
Returns the modified string with the first match replaced.
Examples
Validating an email address
local email_regex = Regex.new("^[\\w.-]+@[\\w.-]+\\.[a-zA-Z]{2,}$")
local valid, _ = email_regex:Status()
if valid then
local is_valid = #email_regex:Match("[email protected]") > 0
print("Is valid email:", is_valid)
else
print("Invalid regex pattern")
end
Extracting numbers from a string
local number_regex = Regex.new("\\d+")
local text = "The price is $15.99 for 3 items"
local numbers = number_regex:Match(text)
for _, number in ipairs(numbers) do
print("Found number:", number)
end