From: Josh Cheek <josh.cheek@...>
Date: 2011-04-27T13:27:53+09:00
Subject: Re: pattern matching and array methods

--bcaec548a06716698604a1dedd10
Content-Type: text/plain; charset=ISO-8859-1

On Tue, Apr 26, 2011 at 11:07 PM, Mfer Dez <emphxl@yahoo.com> wrote:

> I have a text file that is structured like so:
>
> 1:1 abcdefg
> 1:2 abcdefg
> 1:3 abcdefg
> 1:4 abcdefg
> 1:5 abcdefg
>
> I would like to be able to print out a subset of the file ie: print the
> line beginning with 1:2 through the line beginning with 1:4
>
> So far, I've started with this;
>
> lines = File.readlines("file.txt")
>
> This puts each line of the text file into an array, so the lines[] array
> looks like this:
>
> line[0] is 1:1 abcdefg
> line[1] is 1:2 abcdefg
> line[2] is 1:3 abcdefg
> etc.
>
> If I want to print out the lines that start with 1:2 through 1:4, how
> should I proceed? Some of the text files won't be "aligned" in that
> line[0] won't always be 1:1. If a user would like to print the lines
> containing 3:9 - 3:31, how can I scan each line of the array and pattern
> match the boundaries (3:9 - 3:31 in this example)? What array methods
> are available to me.
>
> Thanks in advance for any information that could point me in the right
> direction.
>
> --
> Posted via http://www.ruby-forum.com/.
>
>
I suppose you could use a flip flop... or awk :P



$ cat file.txt
1:1 abcdefg
1:2 abcdefg
1:3 abcdefg
1:4 abcdefg
1:5 abcdefg

$ ruby -e '
> File.foreach ARGV.first do |line|
>   puts line if line.start_with?("1:2")..line.start_with?("1:4")
> end
> ' file.txt
1:2 abcdefg
1:3 abcdefg
1:4 abcdefg

$ awk '$1 == "1:2", $1 == "1:4"' file.txt
1:2 abcdefg
1:3 abcdefg
1:4 abcdefg

--bcaec548a06716698604a1dedd10--