From: kjana@...4lab.to (YANAGAWA Kazuhisa)
Date: 2002-05-06T12:05:02+09:00
Subject: Re: newbie Q: how to strip blank lines from file?

In message <YmlB8.26235$GG6.2378585@news3.calgary.shaw.ca>
stewart@NOWHERE_midwinter.ca writes:

> # IO.foreach("snip.txt") { |line| puts line }

You can skip a blank line to eliminate it from output so....

  IO.foreach("snip.txt") { |line| next if line =~ /^\s*$/; puts line }

here, `next' for forwarding to the next iteration.


> arr = IO.readlines("snip.txt")
> puts "I read in " + arr.length.to_s + "lines from file."
> def blank (s)    # looking for blank lines to chop
>    (s =~ /\S/) != nil
> end
> i = 0
> while i < arr.length do
>  if blank(arr[i]) == nil then arr[i] = nil
> IO.printf("snip.out")
> end
> # file.close("snip.out")
> end

If you prefer reading the whole file into an Array, then you can use
Enumerable#reject (or reject! for in-place modification) for deleting
blank lines like:

  arr.reject { |line| line =~ /^\s*$/ }


Actually File < IO includes Enumerable, so you can....

  puts File.open("snip.txt").reject { |line| line !~ /\S/ }

# but this doesn't close the File.


-- 
kjana@dm4lab.to                                    May 6, 2002
The more haste, the less speed.