From: "David A. Black" <dblack@...>
Date: 2008-03-30T16:14:21+09:00
Subject: Re: inject's pathological case...

Hi --

On Sun, 30 Mar 2008, Just Another Victim of the Ambient Morality wrote:

>    I'm not sure how I feel about inject's pathological case.  What do you
> all think should happen in the following code?
>
>
> [2].inject {|a, i| puts i}
>
>
>    I might have thought that the block would never be called and the method
> would return 2.
>    If the block must be called, I might expect "i" to be nil.
>    What actually happens is that the block is called and "i" is the same
> thing as "a".  I did not expect this and I'm trying to figure out how this
> is either consistent or useful.  Can someone clue me in to this behaviour?
>    Thank you...

Actually the block isn't being called:

   irb(main):005:0> [2].inject {|a, i| puts "hi" }
   => 2
   irb(main):006:0> [2].inject {}
   => 2

The value of the whole statement is 2, or, more generally, the first
(and only) element in the enumerable. I guess that's all it can do
since it doesn't have enough elements to call the block even once.


David

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