Comments on: Enumerating Enumerable: Enumerable#collect/Enumerable#map

By: Enumerating Enumerable: Enumerable#each_with_index < Global Nerdy

Enumerating Enumerable: Enumerable#each_with_index < Global Nerdy — Fri, 01 Aug 2008 05:29:13 +0000

[...] collect / map [...]

By: Enumerating Enumerable: Enumerable#each_slice < Global Nerdy

Enumerating Enumerable: Enumerable#each_slice < Global Nerdy — Thu, 31 Jul 2008 04:47:19 +0000

[...] collect / map [...]

By: Enumerating Enumerable: Enumerable#each_cons « Global Nerdy

Enumerating Enumerable: Enumerable#each_cons « Global Nerdy — Tue, 29 Jul 2008 01:49:00 +0000

[...] collect / map [...]

By: Global Nerdy | Enumerating Enumerable: Enumerable#drop

Global Nerdy | Enumerating Enumerable: Enumerable#drop — Thu, 10 Jul 2008 04:09:18 +0000

[...] collect / map [...]

By: Global Nerdy | Enumerating Enumerable: Enumerable#cycle

Global Nerdy | Enumerating Enumerable: Enumerable#cycle — Sun, 06 Jul 2008 05:14:06 +0000

[...] collect / map [...]

By: This Week in Ruby (June 26, 2008) | Zen and the Art of Programming

This Week in Ruby (June 26, 2008) | Zen and the Art of Programming — Thu, 26 Jun 2008 04:33:35 +0000

[...] there were a numbers of interesting articles: Using select, reject, collect, inject and detect, Enumerating Enumerable, Macros, Hygiene, and Call By Name in Ruby Eliminating code duplication with Metaprogramming. Also [...]

By: Joey deVilla

Joey deVilla — Wed, 25 Jun 2008 18:28:18 +0000

@Reg Braithwaite: Ah, yes. I've been following the Enumerable docs so much that I'd forgotten about some of the similar (and sometimes overlapping) methods in Array. Although collect!/map! are technically in Array, this series is really more about practical results, which means I should update the article to include those methods. Thanks for the heads-up!

By: Reg Braithwaite

Reg Braithwaite — Wed, 25 Jun 2008 18:03:20 +0000

You're discussing Enumerable, so this is slightly tangential... Most folks will encounter these methods for Arrays. The Array class implements destructive versions of these methods suffixed with a bang(!) For example:

a = [1,2,3,4,5]
a.map { |n| n * 2 } => [2,4,6,8,10]
a => [1,2,3,4,5]

But

a.map! { |n| n * 2 } => [2,4,6,8,10]
a =>[2,4,6,8,10]