Question

I’m still learning Ruby so far and working on a small gem that allows you to do something as long as the current file your in includes a certain attribute (in my case ”). I took a look at some of the File class methods and never came across anything I was looking for. I do realize the popular Array method .include?, and I’m wondering if there’s a method for doing this in a bigger scale, which is applying it to the File class. Can anyone point out a File class method or script that does this?

Example:

# The Array class method scans the array for an item
arr = ['foo', 'bar', 'baz']
if arr.include?('foo')
  # (insert text)
end

What I need to do:

if File.include?('')
  # My code
end

Thanks!

Answer 1

Take a look:

if File.read(filename).include? str
  # do your thing
end

Caution: this code reads entire file into memory. You better not apply it to huge files.

This is a more efficient way.

def my_include? filename, str
  File.open(filename, "r") do |file|
    file.each do |line|
      return true if line.include?(str)
    end
  end
  false
end