a = " (55)"
for word in string.gmatch(a, "%f[%w_]%d+") do print(word) end
-- 55
for word in string.gmatch(a, "[()%%+={},:*^-]+") do print(word) end
-- (, )
YSA9ICIgKDU1KSIKZm9yIHdvcmQgaW4gc3RyaW5nLmdtYXRjaChhLCAiJWZbJXdfXSVkKyIpIGRvIHByaW50KHdvcmQpIGVuZAotLSA1NQpmb3Igd29yZCBpbiBzdHJpbmcuZ21hdGNoKGEsICJbKCklJSs9e30sOipeLV0rIikgZG8gcHJpbnQod29yZCkgZW5kCi0tICgsICkK