From: Phrogz <phrogz@...>
Date: 2009-11-22T13:46:19+09:00
Subject: Re: How to match and count

On Nov 21, 8:00 pm, Ruby Newbee <rubynew...@gmail.com> wrote:
> 2009/11/22 Phrogz <phr...@mac.com>:
> > On Nov 21, 7:09 pm, Ruby Newbee <rubynew...@gmail.com> wrote:
> >> awk '{if ($4~/something/) {i+=1}} END {print i}'  file.txt
> >> That means if a line's 4th field match "something" then increase the
> >> counter by 1.
> >> How to write the corresponding ruby code?
> > What is a 'field'? Whitespace delimited?
> Yes, thanks.

Here are two ways:

# Don't read the whole file into memory, but do it one line at a time
i = 0
file = File.open( "foo.txt" )
file.each_line do |line|
  pieces = line.split( /\s+/ )
  i += 1 if pieces[ 3 ] =~ /something/
end


# Just read the whole file at once, assuming it's small enough,
# and create an array of the fourth column's
col = File.read("foo.txt").scan(/.+/).map{ |line| line.scan(/\S+/)
[3] }
i = col.count{ |val| val =~ /something/ }