# Checking File for a line **URL:** \ **Category:** Ruby\ **Created:** [November 23, 2007, 11:29am UTC](https://www.ruby-forum.com/t/checking-file-for-a-line/121065 "2007-11-23T11:29:44Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![jazcyk](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/e56c9b/32.png) [@jazcyk](https://www.ruby-forum.com/u/jazcyk)\ **Post date:** [November 23, 2007, 11:29am UTC](https://www.ruby-forum.com/t/checking-file-for-a-line/121065/1 "2007-11-23T11:29:44Z")
Need to check a file for a line Lets say “this is an example” I am going to just take every line into an array and then have a For loop to check the array for that line. Im pretty sure this will work but is there any cleaner way to do it? ---
**Author:** ![jazcyk](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/e56c9b/32.png) [@jazcyk](https://www.ruby-forum.com/u/jazcyk)\ **Post date:** [November 23, 2007, 12:00pm UTC](https://www.ruby-forum.com/t/checking-file-for-a-line/121065/2 "2007-11-23T12:00:57Z")
Peter L. wrote: > Im pretty sure this will work but is there any cleaner way to do it? File.readlines('file.txt.).each do |line| puts ‘got it!’ if line =~ /regexp/ end Hope the helps. Regards, Lee ---
**Author:** ![jazcyk](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/e56c9b/32.png) [@jazcyk](https://www.ruby-forum.com/u/jazcyk)\ **Post date:** [November 23, 2007, 1:08pm UTC](https://www.ruby-forum.com/t/checking-file-for-a-line/121065/3 "2007-11-23T13:08:28Z")
2007/11/23, Lee J. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid): > Peter L. wrote: > > > Im pretty sure this will work but is there any cleaner way to do it? > > File.readlines('file.txt.).each do |line| > puts ‘got it!’ if line =~ /regexp/ > end This is more efficient - no need to load the whole file into mem to find a single line: File.foreach “file.txt” do |line| if /rx/ =~ line puts “found it” break end end Cheers robert ---
**Author:** ![jazcyk](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/e56c9b/32.png) [@jazcyk](https://www.ruby-forum.com/u/jazcyk)\ **Post date:** [November 23, 2007, 1:45pm UTC](https://www.ruby-forum.com/t/checking-file-for-a-line/121065/4 "2007-11-23T13:45:57Z")
On Nov 23, 1:08 pm, Robert K. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > find a single line: > robert > > – > use.inject do |as, often| as.you\_can - without end Check out ri IO:foreach ri IO#each and use what more suits your needs. Dima ---
**Author:** ![jazcyk](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/e56c9b/32.png) [@jazcyk](https://www.ruby-forum.com/u/jazcyk)\ **Post date:** [November 23, 2007, 6:38pm UTC](https://www.ruby-forum.com/t/checking-file-for-a-line/121065/5 "2007-11-23T18:38:07Z")
2007/11/23, Dejan D. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid): > > This is more efficient - no need to load the whole file into mem to > > and use what more suits your needs. > I am not sure I understand this posting of yours. Are you talking to > the OP or to me? If you are talking to me, foreach is what I used in > the example above. robert ---
**Author:** ![jazcyk](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/e56c9b/32.png) [@jazcyk](https://www.ruby-forum.com/u/jazcyk)\ **Post date:** [November 23, 2007, 7:41pm UTC](https://www.ruby-forum.com/t/checking-file-for-a-line/121065/6 "2007-11-23T19:41:38Z")
> This is more efficient - no need to load the whole file into mem to > find a single line: > > File.foreach “file.txt” do |line| > if /rx/ =~ line > puts “found it” > break > end > end > > Cheers > > robert Ahh, good point, touche my good man. Regards, Lee ---
**Author:** ![jazcyk](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/e56c9b/32.png) [@jazcyk](https://www.ruby-forum.com/u/jazcyk)\ **Post date:** [November 24, 2007, 8:59am UTC](https://www.ruby-forum.com/t/checking-file-for-a-line/121065/7 "2007-11-24T08:59:20Z")
2007/11/23, Lee J. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid): > > Cheers > > > > robert > > Ahh, good point, touche my good man. While we’re at it: there is another solution - probably a bit more elegant: require ‘enumerator’ File.to\_enum(:foreach,“file.txt”).grep(/rx/) {|li| puts li; break} 🙂 Kind regards robert ---
**Author:** ![jazcyk](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/e56c9b/32.png) [@jazcyk](https://www.ruby-forum.com/u/jazcyk)\ **Post date:** [November 25, 2007, 7:11pm UTC](https://www.ruby-forum.com/t/checking-file-for-a-line/121065/8 "2007-11-25T19:11:15Z")
On Nov 24, 8:58 am, Robert K. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > > end > > > File.to\_enum(:foreach,“file.txt”).grep(/rx/) {|li| puts li; break} > > 🙂 > > Kind regards > > robert > > – > use.inject do |as, often| as.you\_can - without end That’s Ruby beauty, express yourself in a way that suits you the most and still we all can understand your dialect and enjoy. Dima ---
**Author:** ![jazcyk](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/e56c9b/32.png) [@jazcyk](https://www.ruby-forum.com/u/jazcyk)\ **Post date:** [November 25, 2007, 8:44pm UTC](https://www.ruby-forum.com/t/checking-file-for-a-line/121065/9 "2007-11-25T20:44:38Z")
Dejan D. wrote: > On Nov 24, 8:58 am, Robert K. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > > > > end > > > > File.to\_enum(:foreach,“file.txt”).grep(/rx/) {|li| puts li; break} > > > > 🙂 > > > > Kind regards > > > > robert > > > > – > > use.inject do |as, often| as.you\_can - without end > > That’s Ruby beauty, express yourself in a way that suits you the most > and still we all can understand your dialect and enjoy. Speak for yourself. I found that solution particularly distasteful. It turned a simple, easy to read solution, into a convoluted one-liner mess. And on my system the enumerator solution is 50% slower. But, that seems to be the Ruby Way, so at some point I guess I’ll have to drink the koolaid and declare how beautiful solutions like that are.