Question

I’m using Ruby to do a simple substring type match. I’m trying to understand why the following happens:

irb(main):024:0> puts "match" if "foo" =~ /foo/
match
=> nil
irb(main):025:0> puts "match" if "foo" =~ /foo,/
=> nil

how can this regex be modified so that if any part of the search criteria matches “foo”, a match is made?

Answer 1

You’ve got your comparisons backwards:

"foo".match(/foo,/) # See if "foo" matches the pattern "foo,"
# => nil
"foo,".match(/foo/) # See if "foo," matches the pattern "foo"
# => #<MatchData "foo"> 

The =~ operator is a bit of history that has fallen out of style because it’s not self-explanatory.