From: William James <w_a_x_man@...>
Date: 2007-01-04T04:35:11+09:00
Subject: Re: Delete line from file


dblack@wobblini.net wrote:
> Hi --
>
> On Wed, 3 Jan 2007, William James wrote:
>
> >
> > Jules wrote:
> >> Hi,
> >>
> >> Given a line number, what is the best way to delete this line from a
> >> file?
> >>
> >> And given an array of line numbers, what is the best way to delete
> >> these lines from a file?
> >>
> >> Thanks,
> >>
> >> Jules
> >
> > lines = IO.readlines('junk1')
> > [1,3,5].each{|n| lines.slice!(n) }
>
> That's going to have a side-effect problem:
>
> irb(main):004:0> a = %w{ a b c d e f }
> => ["a", "b", "c", "d", "e", "f"]
> irb(main):005:0> [1,3,5].each {|e| a.slice!(e) }
> => [1, 3, 5]
> irb(main):006:0> a
> => ["a", "c", "d", "f"]

True.

a = %w(zero one two three four five)
[1,3,5].each{|i| a[i]=nil}
a.compact!