From: Kenichi Kamiya <kachick1@...>
Date: 2012-01-17T19:58:05+09:00
Subject: Re: uniq with count; better way?

Abinoam,
thank you for get the benchmarks.
I guess the different of spped from generating objects.
They generate minimal objects which Object#tap and Enumerable#each_with_object.
-------------------------------------------------------------------------------
Ralph,
I like #1 for comprehensibility meaning

# looks "construct Hash instance from inner subscript"
Hash[]

# looks "collect the own values"
a.group_by{|n|n}

# counting
map{|k, v|[k, v.size]}]

# if Hash has own map
https://gist.github.com/1626034
-------------------------------------------------------------------------------
I like #2 for comprehensibility, clear name-space, and speed meanings

# comprehensibility
# looks like "list comprehension"
tap{|h|a.each{|n|h[n] += 1}}

# clear name-space
no make variables for out of block

# speed meanings
look Abinoam's benchmarks

# if Enumerable has method for this case
https://gist.github.com/1625981

2012/1/17 Ralph Shnelvar <ralphs@dos32.com>:
> Kenichi,
>
> Monday, January 16, 2012, 9:21:51 AM, you wrote:
>
>
>
> KK> 2012/1/17 Ralph Shnelvar <ralphs@dos32.com>:
>>> a = [4,5,6,4,5,6,6,7]
>>>
>>> result = Hash.new(0)
>>> a.each { |x|  result[x] += 1 }
>>>
>>> p result
>>>
>>>
>>>
>>> The result I am getting
>>>   {4=>2, 5=>2, 6=>3, 7=>1}
>>> is what I want.
>>>
>>> Is there a better way; perhaps using uniq?
>>>
>>>
>
>
> KK> I like this
>
> KK> a = [4,5,6,4,5,6,6,7]
>
> KK> # 1
> KK> p Hash[a.group_by{|n|n}.map{|k, v|[k, v.size]}]
>
> KK> # 2
> KK> p Hash.new(0).tap{|h|a.each{|n|h[n] += 1}}
>
>
> I like #2.  I can understand it.  I'm still having trouble wrapping my head around #1.
>
>
> Having said that, is your #2 better than mine in any dimension (comprehensibility and/or speed of execution?
>
>
>

-- 
Kenichi Kamiya