Ruby: What's the proper syntax for a boolean regex method?

Question

What is the proper syntax for a method that checks a string for a pattern, and returns true or false if the regex matches?

Basic idea:

def has_regex?(string)
    pattern = /something/i
    return string =~ pattern
end

Use case:

if has_regex?("something")
    # woohoo
else
    # nothing found: panic!
end

Answer 1

In the question you said:

... method that checks a string for a pattern, and returns true or false if the regex matches

As johannes pointed out String=~ returns nil if the pattern did not match and the position in the string where the matched word stared otherwise. Further he states in Ruby everything except nil and false behave like true. All of this is right.

However, they are not exactly true or false. Therefore, the last step is to coerce the value to be a Boolean. This is achieved by wrapping the result in double bangs returns a true.

def has_regex?(string)
    !!(string =~ /something/i)
end

Answer 2

Your code looks fine, but you could write it even smaller.

The return value of String#=~ behaves this way:

• nil if the pattern did not match
• the position in the string where the matched word started

In Ruby everything except nil and false behaves like true in a conditional statement so you can just write

if string=~ pattern
  # do something
else
  # panic
end