Create regular expression from string

Question

Is there any way to create the regex /func:\[sync\] displayPTS/ from string func:[sync] displayPTS?

The story behind this question is that I have serval string pattens to search against in a text file and I don't want to write the same thing again and again.

 File.open($f).readlines.reject {|l| not l =~ /"#{string1}"/}
 File.open($f).readlines.reject {|l| not l =~ /"#{string2}"/}

Instead , I want to have a function to do the job:

  def filter string
          #build the reg pattern from string
          File.open($f).readlines.reject {|l| not l =~ pattern}
  end
  filter string1
  filter string2

Answer 1

s = "func:[sync] displayPTS"
# => "func:[sync] displayPTS"
r = Regexp.new(s)
# => /func:[sync] displayPTS/
r = Regexp.new(Regexp.escape(s))
# => /func:\[sync\]\ displayPTS/

Answer 2

How about using %r{}:

my_regex = "func:[sync] displayPTS"
File.open($f).readlines.reject { |l| not l =~ %r{#{my_regex}} }