From: lianliming <lianliming@...>
Date: 2007-12-11T18:35:00+09:00
Subject: Re: Find the first non-nil element in an array

Really helpful, thx!

> > Hi all,
>
> > Is there any build-in method of class Array which can be used to find
> > the first non-nil element in an array? I can't find any so I am trying
> > to achieve it by my own approach. I don't think my approach is smart
> > enough, so I would like to know better one to do so. Here is what I am
> > doing:
>
> > a = [nil, "hello", "world"]
> > b = a
> > b.compact!
> > first_non_nil_elem =  b.first
>
> > I don't call "compact!" directly on a because it will change a's
> > structure, I want to reserve nil elements in a.
>
> > Any suggestions are really appreciated!
>
> You can use Enumerable#find, which will return the first item in the array for
> which the block returns true:
>
> a = [nil, "hello", "world"]
> puts a.find{|i| !i.nil?}
> => "hello"
>
> By the way, you can use compact, instead of compact! to avoid using the
> temporary variable b:
>
> a = [nil, "hello", "world"]
> first_non_nil_elem = a.compact.first
>
> While compact! removes the nil elements from the receiver, compact returns a
> new array with the nil element removed.
>
> I hope this helps
>
> Stefano