From: Chad Fowler <chad@...>
Date: 2004-03-11T09:31:18+09:00
Subject: Re: Novice question, tranlate awk code to ruby code


On Mar 10, 2004, at 4:19 PM, Horacio Castellini wrote:

> Hi everyone:
>     I'm a novice ruby user, but ancient user in Linux world. We assume
> have a data file with two data field in two columns. In awk program 
> when I
> like time them a script code may be:
>
> {
>     print $1*$2
> }
>
> for example I can use "% cat foo.dat|awk -f times.awk" d'accorde. Well,
> how can I do this in ruby code?
>

Hi.  Here's a very awk-like way to do it:

cat foo.dat |ruby -ane 'puts $F[0].to_i * $F[1].to_i'

-a autosplits and creates $F, which is an array of the fields on each 
line.

-n creates a loop for each line of input.

-e executes the next arg as a ruby program.

One interesting note if you're coming from awk is that the record 
separator (specified by -F on the command line of both Ruby and awk) 
can accept a regular expression.  So (for a silly example), you could 
have a file like this:

this123123124is524234234a987234872test

and executing
ruby -F[0-9]+ -ane 'puts $F[3]'
...would output "test"


Chad