Comments on: Enumerable#every

By: Nicolas Blanco

Nicolas Blanco — Tue, 14 Apr 2009 13:19:13 +0000

I really like this.
Should be in Rails core for sure!

Nicolas.

By: slothbear

slothbear — Tue, 07 Apr 2009 03:29:53 +0000

Very very nice. Makes it look like .. no … *makes* it real Ruby.

By: mynyml

mynyml — Fri, 03 Apr 2009 15:17:17 +0000

There are benchmarks included in the gem that show the same results. There’s no doubt that #every is slower than native #map, and it is slower than Symbol#to_proc.

On ruby v1.8.7 (100_000 iterations)

                    total        real
#map:            0.170000 (  0.202195)
Symbol#to_proc:  0.150000 (  0.144365)
#every:          0.240000 (  0.251681)

IMO the difference is not significant enough to matter, though. Noone’s expected to use it in a low level library (where you’d probably use native methods as much as possible, or even better, RubyInline ;) ). And 100_000 iterations (or 1_000_000 in your benchmark) is a *lot* of iterations; it’s unlikely your biggest worry will be #every.

By: Ryan Davis

Ryan Davis — Fri, 03 Apr 2009 04:21:52 +0000

# of iterations = 1000000
user system total real
null_time 0.260000 0.000000 0.260000 ( 0.281800)
map 17.120000 0.130000 17.250000 ( 19.205743)
to_proc 44.220000 0.430000 44.650000 ( 50.080658)
every 66.930000 0.670000 67.600000 ( 76.222073)

By: coderrr

coderrr — Thu, 02 Apr 2009 15:31:26 +0000

Hobo has had this for a long time. They use *

User.all.*.contacts.flatten.*.last_name.*.capitalize

http://github.com/tablatom/hobo/blob/d8b5b90d630e3911fab8655275cc043217bc32d8/hobosupport/lib/hobo_support/enumerable.rb

By: mynyml

mynyml — Thu, 02 Apr 2009 05:47:34 +0000

@Shadowfiend Interesting. I didn’t know about Methodphetamine. Pretty clever. Makes for an interesting comparison, actually;

(first three examples from: http://jicksta.com/posts/the-methodphitamine)
User.all.map{|x| x.contacts.map{|y| y.last_name.capitalize }}
User.all.map{|x|x.contacts.map(&:last_name).map(&:capitalize)}
User.all.map &its.contacts.map(&its.last_name.capitalize)
User.all.every.contacts.flatten.every.last_name.every.capitalize

By: Shadowfiend

Shadowfiend — Thu, 02 Apr 2009 05:25:43 +0000

Very sexy. A variant on Symbol#to_proc that allows parameters and multiple method calls is the Methodphetamine (http://jicksta.com/posts/the-methodphitamine). It still uses the & syntax, but without many of the limitations of the more traditional #to_proc solution.

By: mynyml

mynyml — Wed, 01 Apr 2009 23:28:41 +0000

@Luca yes, I’m working on an ActiveSupport patch atm, but it’ll probably be another 2-3 days before I submit it.

@hgs I’m tempted to add other methods too, but at the same time I want to keep the gem as simple as possible. Currently you can have the same results with:

enum = [ "a", "b", "" ]
enum.every.empty?.all? #=> false
enum.every.empty?.any? #=> true

Though I must admit #every? and #some? are sexier names! I’ll definetly keep those in mind. Thanks for the suggestion.

Btw there’s an expiremental branch in the repo that adds the idiom for #select and #reject (@ http://github.com/mynyml/every/tree/expanded)

@Eric glad you liked it!

By: citizen428.blog()

citizen428.blog() — Wed, 01 Apr 2009 21:37:02 +0000

Enumberable#filter…

As much as I like Ruby, some constructs I just don’t find too sexy, e.g.:

[1,2,5,8,7,3,1,9,5].select { |x| x < 5 }

That’s why I came up with alternate solution which I find reads nicer than the above code:

I kinda got inspire…

By: Eric Anderson

Eric Anderson — Wed, 01 Apr 2009 19:01:03 +0000

That is friggen AWESOME.

On one hand I have always felt that Symbol#to_proc was nicer than using a full block. But on the other hand arr.map(&:strip) always felt like too much line noise to be Ruby. Felt like I was moving back to Perl. The lack of arguments and blocks also was annoying as you gsub example demonstrates.

But your solution is makes it work better AND more elegant. I will be using this on many projects/tasks to come.