How to capture a string between parentheses?

Question

str = "fa, (captured)[asd] asf, 31"

for word in str:gmatch("\(%a+\)") do
    print(word) 
end

Hi! I want to capture a word between parentheses.

My Code should print "captured" string.

lua: /home/casey/Desktop/test.lua:3: invalid escape sequence near '\('

And i got this syntax error.

Of course, I can just find position of parentheses and use string.sub function

But I prefer simple code.

Also, brackets gave me a similar error.

Answer 1

The escape character in Lua patterns is %, not \. So use this:

word=str:match("%((%a+)%)")

If you only need one match, there is no need for a gmatch loop.

To capture the string in square brackets, use a similar pattern:

word=str:match("%[(%a+)%]")

If the captured string is not entirely composed of letters, use .- instead of %a+.