Ruby idiom a ||= b means?

ruby-talk
1

What does the ruby idiom a ||= b mean?

Thanks,
Ratnavel

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Posted via http://www.ruby-forum.com/.

2

It is like:
  a || a = b
See David A. Black's Blog
  http://dablog.rubypal.com/2008/3/25/a-short-circuit-edge-case

-Rob

P.S. Please don't ask the same question on both Rails and Ruby lists/forums.

Rob Biedenharn http://agileconsultingllc.com
Rob@AgileConsultingLLC.com

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On Jul 1, 2008, at 12:31 AM, Ratnavel P S wrote:

What does the ruby idiom a ||= b mean?

Thanks,
Ratnavel

3

Ratnavel P S wrote:

What does the ruby idiom a ||= b mean?

It's commonly used to assign default values to things.
This idiom is also very common in Perl, which is presumably where it
came from.

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4

In english, thats: If a is nil or false, then leave it, else assign a
= b.

Often used instead of code like this:

if a.nil? then
   a = b
end

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On Jul 1, 6:49 am, Rob Biedenharn <R...@AgileConsultingLLC.com> wrote:

On Jul 1, 2008, at 12:31 AM, Ratnavel P S wrote:

> What does the ruby idiom a ||= b mean?

It is like:
a || a = b

5

This has been discussed nearly to death at:
http://groups.google.com/group/comp.lang.ruby/browse_thread/thread/fe4fbc48e19105cd/bf7f73380e285aff?lnk=gst&q=Or+equal#bf7f73380e285aff