From: A LeDonne <aledonne.listmail@...>
Date: 2006-05-25T01:23:04+09:00
Subject: Re: rubynuby - confused by method name "inject"

On 5/21/06, Logan Capaldo <logancapaldo@gmail.com> wrote:
>
> On May 21, 2006, at 1:05 AM, Jeff Pritchard wrote:
>
> > If I were to choose a synonym for the "inject" method, I might come up
> > with "collect".  vis. "iterate over these items and collect the
> > results
> > in one answer."  It seems to me that this method does the same thing
> > that the big Latin "E" symbol (Epsilon) does in Mathematics.  Is
> > there a
> > name for that symbol within the math community?  (I mean - besides
> > Epsilon).  Calculus and Physics are "twenty some odd years ago" for
> > me.
>
> I think you mean Sigma. And I believe when you don't refer to it as
> sigma you say "Summation".
>
> But I am not a mathematician, so take what I said with a grain of salt.
>

The big Sigma is often called the n-ary sum operator, and there's a
corresponding big Pi called the n-ary product (it can be implemented
as inject where the operation in the block is *).

So, in math-speak, I think one could say:

inject applies a block pairwise as an n-ary operation over an
Enumerable, with an optional initial value.

This may or may not help anyone understand it. :)

-A