# 2 Arrays into 1 Array with all possible combinations?
**URL:** https://rubytalk.org/t/2-arrays-into-1-array-with-all-possible-combinations/68895
**Category:** ruby-talk
**Created:** [19 December 2013 01:37 UTC](https://rubytalk.org/t/2-arrays-into-1-array-with-all-possible-combinations/68895 "2013-12-19T01:37:58Z")
**Posts on this page:** 10
**Page:** 1
### Author:  [@7stud2](https://rubytalk.org/u/7stud2)
#### Post date: [19 December 2013 01:37 UTC](https://rubytalk.org/t/2-arrays-into-1-array-with-all-possible-combinations/68895/1 "2013-12-19T01:37:58Z")
I have 2 arrays like so:
arr1 = [a, b, c]
arr2 = 1, 2, 3]
I want to get:
[a1, a2, a3, b1, b2, b3, c1, c2, c3]
I've tried a few things like
output = arr1.each do |a1|
arr2.each do |a2|
end
end
puts output
But that only lists the first array.
This works:
output = arr1.each do |a1|
arr2.each do |a2|
puts a1 + a2
end
end
But my "output" variable isn't good. I get the desired text in the
console, but I can't reuse it for what I really want to do.
This seems trivial, but I feel stupid. I can't even search for this
properly. Please help... thanks.
> **···**
>
> --
> Posted via [http://www.ruby-forum.com/](http://www.ruby-forum.com/).
---
### Author:  [@Ammar\_Ali](https://rubytalk.org/u/Ammar_Ali)
#### Post date: [19 December 2013 01:57 UTC](https://rubytalk.org/t/2-arrays-into-1-array-with-all-possible-combinations/68895/2 "2013-12-19T01:57:32Z")
> I have 2 arrays like so:
>
> arr1 = [a, b, c]
> arr2 = 1, 2, 3]
>
> I want to get:
>
> [a1, a2, a3, b1, b2, b3, c1, c2, c3]
Here’s one way:
> > a1 = %w{a b c}
=\> ["a", "b", "c"]
> > a2 = %w{1 2 3}
=\> ["1", "2", "3"]
> > a1.map {|c1| a2.map {|c2| c1 + c2} }.flatten
=\> ["a1", "a2", "a3", "b1", "b2", "b3", "c1", "c2", "c3”]
HTH,
Ammar
> **···**
>
> On Dec 19, 2013, at 3:37 AM, Mike Lerner \ wrote:
---
### Author:  [@7stud2](https://rubytalk.org/u/7stud2)
#### Post date: [20 December 2013 11:27 UTC](https://rubytalk.org/t/2-arrays-into-1-array-with-all-possible-combinations/68895/3 "2013-12-20T11:27:58Z")
ar1=['a','b','c']
ar2=[1,2,3]
ar3=Array.new()
ar1.each do |a| ar2.each do |n| ar3.push(a+n.to\_s) end end
p ar3
> **···**
>
> --
> Posted via [http://www.ruby-forum.com/](http://www.ruby-forum.com/).
---
### Author:  [@abinoam](https://rubytalk.org/u/abinoam)
#### Post date: [19 December 2013 02:09 UTC](https://rubytalk.org/t/2-arrays-into-1-array-with-all-possible-combinations/68895/4 "2013-12-19T02:09:37Z")
a1 = ["a", "b", "c"]
a2 = ["1", "2", "3"]
a1.product(a2)
# =\> [["a", "1"], ["a", "2"], ["a", "3"], ["b", "1"], ["b", "2"],
["b", "3"], ["c", "1"], ["c", "2"], ["c", "3"]]
a1.product(a2).map {|a| a.join }
# =\> ["a1", "a2", "a3", "b1", "b2", "b3", "c1", "c2", "c3"]
a1.product(a2).map(&:join)
# =\> ["a1", "a2", "a3", "b1", "b2", "b3", "c1", "c2", "c3"]
# same as above
# If you want to different things with one element
a1.product(a2).map {|el1, el2| el1.upcase + el2 }
=\> ["A1", "A2", "A3", "B1", "B2", "B3", "C1", "C2", "C3"]
Best regards,
Abinoam Jr.
> **···**
>
> On Wed, Dec 18, 2013 at 10:57 PM, Ammar Ali \ wrote:
>
> > On Dec 19, 2013, at 3:37 AM, Mike Lerner \ wrote:
> >
> > > I have 2 arrays like so:
> > >
> > > arr1 = [a, b, c]
> > > arr2 = 1, 2, 3]
> > >
> > > I want to get:
> > >
> > > [a1, a2, a3, b1, b2, b3, c1, c2, c3]
> >
> > Here’s one way:
> >
> > > > a1 = %w{a b c}
> >
> > =\> ["a", "b", "c"]
> >
> > > > a2 = %w{1 2 3}
> >
> > =\> ["1", "2", "3"]
> >
> > > > a1.map {|c1| a2.map {|c2| c1 + c2} }.flatten
> >
> > =\> ["a1", "a2", "a3", "b1", "b2", "b3", "c1", "c2", "c3”]
> >
> > HTH,
> > Ammar
---
### Author:  [@7stud2](https://rubytalk.org/u/7stud2)
#### Post date: [19 December 2013 02:11 UTC](https://rubytalk.org/t/2-arrays-into-1-array-with-all-possible-combinations/68895/5 "2013-12-19T02:11:24Z")
> > > a1 = %w{a b c}
>
> =\> ["a", "b", "c"]
>
> > > a2 = %w{1 2 3}
>
> =\> ["1", "2", "3"]
>
> > > a1.map {|c1| a2.map {|c2| c1 + c2} }.flatten
>
> =\> ["a1", "a2", "a3", "b1", "b2", "b3", "c1", "c2", "c3]
That's it! Thank you!
> **···**
>
> --
> Posted via [http://www.ruby-forum.com/\](http://www.ruby-forum.com/%5C).
---
### Author:  [@stomar](https://rubytalk.org/u/stomar)
#### Post date: [19 December 2013 05:31 UTC](https://rubytalk.org/t/2-arrays-into-1-array-with-all-possible-combinations/68895/6 "2013-12-19T05:31:14Z")
@Ammar: "\>\>" is rendered as quote by many email clients,
so using it as prompt is not so good in a mailing list.
Regards,
Marcus
> **···**
>
> Am 19.12.2013 02:57, schrieb Ammar Ali:
>
> > Here’s one way:
> >
> > > > a1 = %w{a b c}
> >
> > =\> ["a", "b", "c"]
> >
> > > > a2 = %w{1 2 3}
> >
> > =\> ["1", "2", "3"]
> >
> > > > a1.map {|c1| a2.map {|c2| c1 + c2} }.flatten
> >
> > =\> ["a1", "a2", "a3", "b1", "b2", "b3", "c1", "c2", "c3”]
>
> --
> GitHub: [stomar (Marcus Stollsteimer) · GitHub](https://github.com/stomar/)
> PGP: 0x6B3A101Amm
---
### Author:  [@Ammar\_Ali](https://rubytalk.org/u/Ammar_Ali)
#### Post date: [19 December 2013 07:53 UTC](https://rubytalk.org/t/2-arrays-into-1-array-with-all-possible-combinations/68895/7 "2013-12-19T07:53:06Z")
I actually like Abinoam’s suggestion better.
a1.product(a2).map(&:join)
Regards,
Ammar
> **···**
>
> On Dec 19, 2013, at 4:11 AM, Mike Lerner \ wrote:
>
> > That's it! Thank you!
---
### Author:  [@John\_Moon](https://rubytalk.org/u/John_Moon)
#### Post date: [20 December 2013 16:16 UTC](https://rubytalk.org/t/2-arrays-into-1-array-with-all-possible-combinations/68895/8 "2013-12-20T16:16:55Z")
ar3 = [ar1, ar2]
ar3.flatten.permutation.map(&:join)
> **···**
>
> On Fri, Dec 20, 2013 at 6:27 AM, Selvag Ruby \ wrote:
>
> > ar1=['a','b','c']
> > ar2=[1,2,3]
> > ar3=Array.new()
> >
> > ar1.each do |a| ar2.each do |n| ar3.push(a+n.to\_s) end end
> > p ar3
> >
> > --
> > Posted via [http://www.ruby-forum.com/\](http://www.ruby-forum.com/%5C).
>
> --
> John Moon
---
### Author:  [@Ammar\_Ali](https://rubytalk.org/u/Ammar_Ali)
#### Post date: [19 December 2013 07:50 UTC](https://rubytalk.org/t/2-arrays-into-1-array-with-all-possible-combinations/68895/9 "2013-12-19T07:50:50Z")
I did not notice that. Thanks for pointing it out.
Regards,
Ammar
> **···**
>
> On Dec 19, 2013, at 7:31 AM, sto.mar@web.de wrote:
>
> > @Ammar: "\>\>" is rendered as quote by many email clients,
> > so using it as prompt is not so good in a mailing list.
---
### Author:  [@abinoam](https://rubytalk.org/u/abinoam)
#### Post date: [19 December 2013 14:27 UTC](https://rubytalk.org/t/2-arrays-into-1-array-with-all-possible-combinations/68895/10 "2013-12-19T14:27:52Z")
Thanks.
Yukihiro Matsumoto: Ruby inherited the Perl philosophy of having MORE
THAN ONE WAY to do the same thing.
([http://www.artima.com/intv/rubyP.html\](http://www.artima.com/intv/rubyP.html%5C))
That's why it's a cool language !!! 😉
> **···**
>
> On Thu, Dec 19, 2013 at 4:53 AM, Ammar Ali \ wrote:
>
> > On Dec 19, 2013, at 4:11 AM, Mike Lerner \ wrote:
> >
> > > That's it! Thank you!
> >
> > I actually like Abinoam’s suggestion better.
> >
> > a1.product(a2).map(&:join)
> >
> > Regards,
> > Ammar