From: Todd Benson <caduceass@...>
Date: 2007-06-04T03:59:27+09:00
Subject: Re: delete in Array (if exist) and count

On 6/3/07, Josselin <josselin@wanadoo.fr> wrote:
> On 2007-06-03 16:57:43 +0200, "Todd Benson" <caduceass@gmail.com> said:
>
> > On 6/3/07, Josselin <josselin@wanadoo.fr> wrote:
> >> I am trying to delete an element from an array if it exists and count
> >> the number of item afterwards
> >>
> >> I wrote
> >>
> >> anArray = [1,2,3,4,5,6,7,8,9]
> >> anArray.size
> >> => 9
> >> anArray.map {|e| e if e != 4}.compact
> >> => [1, 2, 3, 5, 6, 7, 8, 9]
> >>  anArray.map {|e| e if e != 4}.compact.size
> >> => 8
> >>
> >>
> >> is ther a better way to do it... it it's enough ? (learning always how
> >> to write better code..)
> >
> > Array#delete works also with no need for a block (i.e. you're only
> > checking for equality)
> >
> > anArray = [1,2,3,4,5,6]
> > p anArray.delete(4)
> > p anArray.size
>
> I checked
> anArray.delete(0)
> => nil
> then
> anArray.delete(0).size
> NoMethodError: undefined method `size' for nil:NilClass
>
> as I tried to write it in one line....
>
> thanks
>
> joss

That's because Array#delete returns the deletion, not the Array
itself, so, if it has to be on one line, then:

(anArray.delete(4); a).size

or

anArray.delete_if {|i| i == 4}.size

or I prefer

anArray.reject! {|i| i == 4}.size

#delete, #delete_if, and #reject! all change the array while #reject does not