# How to copy arrays? **URL:** \ **Category:** Ruby\ **Created:** [November 21, 2007, 4:20am UTC](https://www.ruby-forum.com/t/how-to-copy-arrays/120848 "2007-11-21T04:20:17Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![martin\_mercy2001](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/d2c977/32.png) [@martin\_mercy2001](https://www.ruby-forum.com/u/martin_mercy2001)\ **Post date:** [November 21, 2007, 4:20am UTC](https://www.ruby-forum.com/t/how-to-copy-arrays/120848/1 "2007-11-21T04:20:17Z")
I came accross another problem, how to copy arrays? Actually i need to copy array just like in java. i will include the source code of java. The same functionality i need in ruby. please any body help me with this ``` System.arraycopy(elName, 0, arr, 0, elStackSize); ``` I need a way to do samething in ruby. please any body help me with code for arraycopy. thanks in advance ---
**Author:** ![martin\_mercy2001](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/d2c977/32.png) [@martin\_mercy2001](https://www.ruby-forum.com/u/martin_mercy2001)\ **Post date:** [November 21, 2007, 4:27am UTC](https://www.ruby-forum.com/t/how-to-copy-arrays/120848/2 "2007-11-21T04:27:33Z")
On Nov 21, 2007 2:20 PM, Martin D. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > The java doesn’t mean anything to me 🙂 That make me very happy. @array.dup is the way to copy any object in ruby ---
**Author:** ![martin\_mercy2001](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/d2c977/32.png) [@martin\_mercy2001](https://www.ruby-forum.com/u/martin_mercy2001)\ **Post date:** [November 21, 2007, 4:38am UTC](https://www.ruby-forum.com/t/how-to-copy-arrays/120848/3 "2007-11-21T04:38:38Z")
Thank you daniel, but my functionality is not return as a array. I need to copy a source array to a destination array. Thank you in advance ---
**Author:** ![martin\_mercy2001](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/d2c977/32.png) [@martin\_mercy2001](https://www.ruby-forum.com/u/martin_mercy2001)\ **Post date:** [November 21, 2007, 4:42am UTC](https://www.ruby-forum.com/t/how-to-copy-arrays/120848/4 "2007-11-21T04:42:46Z")
On Wed, Nov 21, 2007 at 12:38:36PM +0900, Martin D. wrote: > Thank you daniel, but my functionality is not return as a array. > I need to copy a source array to a destination array. def java\_inspired\_method\_sans\_idiomatic\_ruby(destination\_array) destination\_array.replace @my\_array end > Thank you in advance > –Greg ---
**Author:** ![martin\_mercy2001](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/d2c977/32.png) [@martin\_mercy2001](https://www.ruby-forum.com/u/martin_mercy2001)\ **Post date:** [November 21, 2007, 5:14am UTC](https://www.ruby-forum.com/t/how-to-copy-arrays/120848/5 "2007-11-21T05:14:53Z")
On Behalf Of Martin D.: # Thank you daniel, but my functionality is not return as a array. # I need to copy a source array to a destination array. i think you only want to copy a part (the whole is trivial) of the array and insert it to another array, no? a #=\> [1, 2, 3, 4] b #=\> [5, 6, 7, 8, 9, 10] a[1,1] #=\> [2] b[2…-2] #=\> [7, 8, 9] a[1,1]=b[2…-2] #=\> [7, 8, 9] a #=\> [1, 7, 8, 9, 3, 4] or maybe just plain insert it, a[0] #=\> 1 b[0,2] #=\> [5, 6] a[0]=b[0,2] #=\> [5, 6] a #=\> [[5, 6], 7, 8, 9, 3, 4] kind regards -botp ---
**Author:** ![martin\_mercy2001](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/d2c977/32.png) [@martin\_mercy2001](https://www.ruby-forum.com/u/martin_mercy2001)\ **Post date:** [November 21, 2007, 4:45am UTC](https://www.ruby-forum.com/t/how-to-copy-arrays/120848/6 "2007-11-21T04:45:41Z")
On Nov 21, 2007 2:38 PM, Martin D. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Thank you daniel, but my functionality is not return as a array. > I need to copy a source array to a destination array. > > ## Thank you in advance > > Posted via [http://www.ruby-forum.com/](http://www.ruby-forum.com/). I don’t understand what your asking then. This is a fairly standard way to copy an object. @array = [1,2,3,4,5] @new\_array = @array.dup ---
**Author:** ![martin\_mercy2001](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/d2c977/32.png) [@martin\_mercy2001](https://www.ruby-forum.com/u/martin_mercy2001)\ **Post date:** [November 21, 2007, 8:00am UTC](https://www.ruby-forum.com/t/how-to-copy-arrays/120848/7 "2007-11-21T08:00:52Z")
On 21.11.2007 04:38, Martin D. wrote: > Thank you daniel, but my functionality is not return as a array. > I need to copy a source array to a destination array. Maybe before we go off guessing you can show a bit more of your code. While there are methods to copy and insert into another array, maybe there is a more efficient solution. Cheers robert ---
**Author:** ![martin\_mercy2001](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/d2c977/32.png) [@martin\_mercy2001](https://www.ruby-forum.com/u/martin_mercy2001)\ **Post date:** [November 21, 2007, 8:02am UTC](https://www.ruby-forum.com/t/how-to-copy-arrays/120848/8 "2007-11-21T08:02:02Z")
On 21.11.2007 07:58, Robert K. wrote: > On 21.11.2007 04:38, Martin D. wrote: > > > Thank you daniel, but my functionality is not return as a array. > > I need to copy a source array to a destination array. > > Maybe before we go off guessing you can show a bit more of your code. > While there are methods to copy and insert into another array, maybe > there is a more efficient solution. I meant to include this irb(main):007:0\> a=(1…10).to\_a =\> [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] irb(main):008:0\> a[2,4]=%w{a b c} =\> [“a”, “b”, “c”] irb(main):009:0\> a =\> [1, 2, “a”, “b”, “c”, 7, 8, 9, 10] irb(main):010:0\> a.concat %w{foo bar} =\> [1, 2, “a”, “b”, “c”, 7, 8, 9, 10, “foo”, “bar”] irb(main):011:0\> a =\> [1, 2, “a”, “b”, “c”, 7, 8, 9, 10, “foo”, “bar”] irb(main):012:0\> robert