From: Robert Klemme <bob.news@...>
Date: 2005-05-13T16:25:28+09:00
Subject: Re: {} vs begin/end [was Re: object loops and what they return]

Martin DeMello wrote:
> Brian Schr�der <ruby.brian@gmail.com> wrote:
>>
>> print "100! = "
>> puts (1..100).inject(1) { |r,v|
>>   r*v
>> }
>
> Tangentially, inject uses the first value of the enumerable as the
> seed if you don't supply one (the joys of dynamic typing!), so you
> can simply say (1..100).inject {|r,v| r*v}

This might or might not work, depending on the requirements of the
surrounding code:

>> [].inject(1){|a,b| a*b}
=> 1
>> [].inject{|a,b| a*b}
=> nil
>> [].inject(0){|a,b| a+b}
=> 0
>> [].inject{|a,b| a+b}
=> nil

:-))

If you want to detect the case where there are no elements go without the
argument.  If you don't care and just want the sum / product provide an
argument (the neutral element of the operation).

Kind regards

    robert