From: Joel VanderWerf <joelvanderwerf@...>
Date: 2010-10-12T13:04:59+09:00
Subject: Re: more idiomatic way to avoid errors when calling method on variable that may be nil?

On 10/11/2010 08:44 PM, Charles Calvert wrote:
> On Mon, 11 Oct 2010 22:01:43 -0500, "ara.t.howard"
> <ara.t.howard@gmail.com>  wrote in
> <0b78a0a6-c2f2-4321-92bc-d7e6acc5c869@d25g2000yqc.googlegroups.com>:
>
>>
>> var = hash[key].downcase if hash[key]
>
> This is a variant of:
>
> var = hash[key].downcase unless hash[key].nil?
>
> which I indicated in my original post won't work, as I want an
> explicit assignment of nil to var in the event that hash[key] returns
> nil.  See David Black's response to my post.  I'm not assuming that
> this is the first occurrence of var, so it may already have a value
> from a previous assignment.

You can get around this by putting ( ) around the whole if clause:

var = (hash[key].downcase if hash[key])

It works because (... if ...) returns nil if the condition is false.