From: Florian Gilcher <flo@...>
Date: 2010-04-15T22:53:44+09:00
Subject: Re: 1.9's New Methods


On Apr 15, 2010, at 1:06 PM, Intransition wrote:

> First a big shout-out to Marc-Andre Lafortune and his <a href="http://
> github.com/marcandre/backports">backports</a> project. Nice work.
> 
> Now I want to ask if others have noticed all the new methods being add
> to 1.9+? I'm quite happy about vast majority of it, but there was at
> least one method I thought pretty peculiar. This Enumerable method:
> 
>  def flat_map(&block)
>    return to_enum(:flat_map) unless block_given?
>    map(&block).flatten(1)
>  end unless method_defined? :flat_map
>  Backports.alias_method self, :collect_concat, :flat_map
> 
> I am very curious to know how it was decided that a normal map
> followed by a 1-deep flatten is common enough to warrant its own
> method? Two in fact!
> 

One advantage of :flat_map over map(...).flatten(...) is that it can be chained in an Enumerator.

Sometimes, this can come in handy. 

Regards,
Florian Gilcher