Question

I’m trying to parse some code with a ruby script, at some point I want to separate a String into substrings by using match:

frase = "EXTREM(TIME2,FRE,NFRE,SDV,DEL,RMG)"

frase.match(/(\w*)\((.*)\)/)
=> #<MatchData "EXTREM(TIME2,FRE,NFRE,SDV,DEL,RMG)" 1:"EXTREM" 2:"TIME2,FRE,NFRE,SDV,DEL,RMG">

it works as expected on irb, but when I put this in a script file (inside a function called procesa):

tmpo = extra.match(/(\w*)\s*\((.*)\)/)
puts "#{nombre} calls #{tmpo[1]} with #{tmpo[2]}"

I get this error:

`block in procesa': undefined method `[]' for nil:NilClass (NoMethodError)
from f2f90.rb:141:in `each_index'
from f2f90.rb:141:in `procesa'
from f2f90.rb:166:in `block in <main>'
from f2f90.rb:166:in `each'
from f2f90.rb:166:in `<main>'

I’ve searched this site and google with no luck, am I missing something?, I ended up putting extra.match(/(\w*)\s*(.*)/) and tmpo[2].sub("(","").sub(")","") instead but I don’t think its the best way of doing it, and I want to know why the first expression is wrong. Thanks in advance.

Answer 1

That error simply means there is no match. Perhaps if you print out nombre before running the regex you might see why the regex didn’t match the string.