Interpolating a string into a regex

I need to substitute the value of a string into my regular expression in Ruby. Is there an easy way to do this? For example:

foo = "0.0.0.0"
goo = "here is some other stuff 0.0.0.0" 
if goo =~ /value of foo here dynamically/
  puts "success!"
end

Solution 1:

Same as string insertion.

if goo =~ /#{Regexp.quote(foo)}/
#...

Solution 2:

Note that the Regexp.quote in Jon L.'s answer is important!

if goo =~ /#{Regexp.quote(foo)}/

If you just do the "obvious" version:

if goo =~ /#{foo}/

then the periods in your match text are treated as regexp wildcards, and "0.0.0.0" will match "0a0b0c0".

Note also that if you really just want to check for a substring match, you can simply do

if goo.include?(foo)

which doesn't require an additional quoting or worrying about special characters.