a deepcopy for "array = [1,2,3]*5"?
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Newsgroups: comp.lang.ruby
From: "Boris" <bvsch...@gmail.com>Date: 23 May 2005 05:18:16 -0700
Local: Mon, May 23 2005 8:18 am
Subject: a deepcopy for "array = [1,2,3]*5"?
Been looking this up in the myriad of deepcopy strands, but couldn't
find it in 30 minutes, so I'm posting the question.
The question is simple. What way would you create an array that
contains 5 copies of an array, without the copies interfering with each
other?
array = [1,2,3]*5
generates:
[[1,2,3],[1,2,3],[1,2,3],[1,2,3],[1,2,3]]
but unfortunately also makes 'array[1][1] = "a"' change it like this:
[[1,"a",3],[1,"a",3],[1,"a",3],[1,"a",3],[1,"a",3]]
---------
Anyway, found a solution during tinkering, although I don't know why.
Thought I'd just still post it anyway.
ar = []
5.times{ar << [1,2,3]}
works, and 'array[1][1] = "a"' results in the thing I want
[[1,2,3],[1,"a",3],[1,2,3],[1,2,3],[1,2,3]]
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Newsgroups: comp.lang.ruby
From: Brian Schröder <ruby.br...@gmail.com>Date: Mon, 23 May 2005 21:29:01 +0900
Local: Mon, May 23 2005 8:29 am
Subject: Re: a deepcopy for "array = [1,2,3]*5"?
On 23/05/05, Boris <bvsch...@gmail.com> wrote:
> Been looking this up in the myriad of deepcopy strands, but couldn't > find it in 30 minutes, so I'm posting the question. > The question is simple. What way would you create an array that
> contains 5 copies of an array, without the copies interfering with each
> other?
> array = [1,2,3]*5
> generates:
> [[1,2,3],[1,2,3],[1,2,3],[1,2,3],[1,2,3]]
> but unfortunately also makes 'array[1][1] = "a"' change it like this:
> [[1,"a",3],[1,"a",3],[1,"a",3],[1,"a",3],[1,"a",3]]
> ---------
> Anyway, found a solution during tinkering, although I don't know why.
> Thought I'd just still post it anyway.
> ar = []
> 5.times{ar << [1,2,3]}
> works, and 'array[1][1] = "a"' results in the thing I want
> [[1,2,3],[1,"a",3],[1,2,3],[1,2,3],[1,2,3]]
irb(main):001:0> [1,2,3]*5
=> [1, 2, 3, 1, 2, 3, 1, 2, 3, 1, 2, 3, 1, 2, 3]
For what you want you could use:
irb(main):002:0> a = Array.new(5) { [1,2,3] }
=> [[1, 2, 3], [1, 2, 3], [1, 2, 3], [1, 2, 3], [1, 2, 3]]
irb(main):003:0> a[1][1] = 'a'
=> "a"
irb(main):004:0> a
=> [[1, 2, 3], [1, "a", 3], [1, 2, 3], [1, 2, 3], [1, 2, 3]]
$ ruby -v
ruby 1.8.2 (2005-04-11) [i386-linux]
Which version of ruby are you using?
best regards,
Brian Schröder
--
http://ruby.brian-schroeder.de/
Stringed instrument chords: http://chordlist.brian-schroeder.de/
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Newsgroups: comp.lang.ruby
From: "Florian Frank" <fl...@nixe.ping.de>Date: Mon, 23 May 2005 21:28:08 +0900
Local: Mon, May 23 2005 8:28 am
Subject: Re: a deepcopy for "array = [1,2,3]*5"?
On 2005-05-23 21:20:17 +0900, Boris wrote:
> The question is simple. What way would you create an array that
> contains 5 copies of an array, without the copies interfering with each
> other?
array = Array.new(5) { [1,2,3] }
--
Florian Frank
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Newsgroups: comp.lang.ruby
From: Premshree Pillai <premshree.pil...@gmail.com>Date: Mon, 23 May 2005 23:58:43 +0900
Local: Mon, May 23 2005 10:58 am
Subject: Re: a deepcopy for "array = [1,2,3]*5"?
On 5/23/05, Brian Schröder <ruby.br...@gmail.com> wrote:
> For me [1,2,3]*5 behaves different. > irb(main):001:0> [1,2,3]*5
> => [1, 2, 3, 1, 2, 3, 1, 2, 3, 1, 2, 3, 1, 2, 3]
--
Premshree Pillai
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