Check if file contains string

Question

So I found this question on here, but I\'m having an issue with the output and how to handle it with an if statement. This is what I have, but it\'s always saying that it\'s tru

Answer 1

I would use:

if File.readlines("testfile.txt").grep(/monitor/).any?

or

if File.readlines("testfile.txt").any?{ |l| l['monitor'] }

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Using readlines has scalability issues though as it reads the entire file into an array. Instead, using foreach will accomplish the same thing without the scalability problem:

if File.foreach("testfile.txt").grep(/monitor/).any?

or

if File.foreach("testfile.txt").any?{ |l| l['monitor'] }

See "Why is "slurping" a file not a good practice?" for more information about the scalability issues.