From: Robert Klemme <shortcutter@...>
Date: 2007-08-06T23:44:15+09:00
Subject: Re: pulling specific dup. elements out of an array

2007/8/4, Jon Hawkins <globyy3000@hotmail.com>:
> Chris wrote:
> > why didn't reject work?
> >
> >>> array =  ['234234','04593','4098234','0','0','0']
> > => ["234234", "04593", "4098234", "0", "0", "0"]
> >>> array.reject {|e| e == '0' }
> > => ["234234", "04593", "4098234"]
>
> well lemme further explain what im attempting to do and why i couldnt
> get reject to work right, i need to delete all the 0's in the array then
> add up those non-zero numbers.
> with:
>
>  array.inject(0) {|num, i| num + i}/array.length/1024   #1024 =
> kilobytes convert
>
> so if theres a way to shove reject into that then lemme know ^^

Just a small remark: you do not have numbers in your array but
strings. I assume you want to using numeric addition and not string
concatenation.  In that case I'd do:

irb(main):001:0> array =  ['234234','04593','4098234','0','0','0']
=> ["234234", "04593", "4098234", "0", "0", "0"]
irb(main):002:0> nums = array.inject([]) {|a,n| a << n.to_i unless n == "0"; a}
=> [234234, 4593, 4098234]
irb(main):003:0> avg = nums.inject(0) {|s,n| s+n}.to_f / nums.size / 1024
=> 1411.8037109375

Alternative if you prefer a single pass:

irb(main):018:0> sum,count = array.inject([0,0]) {|(s,c),n| n == "0" ?
[s,c] : [s+n.to_i,c+1]}
=> [4337061, 3]
irb(main):019:0> avg = sum.to_f / count / 1024
=> 1411.8037109375

Kind regards

robert