string.format

string.format("%s %q", "Hello", "Lua user!")   -- string and quoted string

Hello "Lua user!"

string.sub("taaaaaaest.lua",1,-5)

taaaaaaest

gmatch

for word in string.gmatch("Hello Lua user", "%a+") do
    print(word)
end

Hello
Lua
user

• match pattern in lua

%d matches a digit
%u matches an uppercase letter
%a: letter %s: whitespace

string.match("%*^", '%%%*%^')

%*^