From: Stefano Crocco <stefano.crocco@...>
Date: 2009-12-22T22:53:29+09:00
Subject: Re: newbie: if is not null else...

On Tuesday 22 December 2009, Alfonso Caponi wrote:
> |Hi forum,
> |
> |how can I replace this PHP syntax with Ruby?
> |
> |$x = (isset($x) and !empty($x)) ? $x : '-';
> |
> |I would like assign a default value if $x is Null.
> |
> |Thank you very much,
> |Al

I don't know PHP, so I'm not sure whether this does exactly what you want:

$x ||= '-'

This is a short form for 

$x = $x || '-'

The right hand side of this expression returns $x if it exists and isn't nil 
or false and '-' otherwise. Note that this won't work if $x can contain the 
value false. In this case, you'll have to use a longer expression:

$x = '-' if $x.nil?

However, the above line will produces a warning if $x hasn't been used before. 
If you don't want this, you need something longer still:

$x = '-' if (!defined? $x or $x.nil?)

I hope this helps

Stefano