From: Eric Hodel <drbrain@...7.net>
Date: 2006-05-26T07:18:15+09:00
Subject: Re: Array#delete_if! - a method to delete and return all array items for which the block evaluates to true.

On May 25, 2006, at 3:15 PM, Eric Hodel wrote:

> On May 25, 2006, at 3:03 PM, Alder Green wrote:
>
>> Here's a method to delete and return all items in an Array for which
>> the block evaluates to true:
>
> [...]
>
>> Would people suggest better implementations?  The obvious problem  
>> here
>> is that we're duplicating arr (to_delete and to_keep contatin  
>> together
>> a cloned arr). I came up with an index based solution to avoid that,
>> but frankly it was quite ugly.
>
> $ ri Array#reject!

Oops, I meant:

$ ri partition
--------------------------------------------------- Enumerable#partition
      enum.partition {| obj | block }  => [ true_array, false_array ]
------------------------------------------------------------------------
      Returns two arrays, the first containing the elements of _enum_  
for
      which the block evaluates to true, the second containing the rest.

         (1..6).partition {|i| (i&1).zero?}   #=> [[2, 4, 6], [1, 3, 5]]

-- 
Eric Hodel - drbrain@segment7.net - http://blog.segment7.net
This implementation is HODEL-HASH-9600 compliant

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