Merge two arrays?

[Joshua Muheim]

Hi all

What's the easiest way to merge two arrays?

Thanks a lot,
Josh

 

[Brian Mitchell]

What's the easiest way to merge two arrays?

It really depends on what you mean by merge.

You could do stuff like:

[1,2] + [2,3] #=3D> [1,2,2,3]
[1,2] | [2,3] #=3D> [1,2,3]

Some motivation for the question might help use in giving you good pointers=

 

[Joshua Muheim]

This already anwers my question, thank you.

 

[Joshua Muheim]

This already anwers my question, thank you.

Hrm oke, got another related question.

array1 = [1,2,4,6]
array2 = [1,3,5,6]

Is there an easy way for doing this?

array1 ?? array2 = [1,6] # Only add entries that occur in both arrays
array1 ?? array2 = [2,3,4,5] # Only add entries that occur in one of
both arrays

 

[Brian Mitchell]

array1 =3D [1,2,4,6]
array2 =3D [1,3,5,6]

Is there an easy way for doing this?

array1 ?? array2 =3D [1,6] # Only add entries that occur in both arrays
array1 ?? array2 =3D [2,3,4,5] # Only add entries that occur in one of
both arrays

array1 & array2 #=3D> [1,6]

the second is harder but you could do it like:
(array1 + array2) - (array1 & array2) #=3D> [2,3,4,5]

I am not sure if that can be made simpler but it should work.

Brian.

 

[Joshua Muheim]

Thanks a lot.

 

[YANAGAWA Kazuhisa]

In Message-Id: <[email protected]>

array1 = [1,2,4,6]
array2 = [1,3,5,6]

array1 ?? array2 = [1,6] # Only add entries that occur in both arrays
array1 ?? array2 = [2,3,4,5] # Only add entries that occur in one of
both arrays

For former Array#& can be used if there're no duplicated elements in
your arrays. For latter, hmm, I can't remember no one methods but you
can (array1|array2)-(array1&array2), on same assumption.

Note these operators always make a new array for a result, they may
not be suitable when both your arrays are too large, though

 

[Joshua Muheim]

For former Array#& can be used if there're no duplicated elements in

your arrays.

Hrm I don't really got this... Where do I have to put the references
(array1, array2) for this?

Note these operators always make a new array for a result, they may
not be suitable when both your arrays are too large, though

Thanks for the hint. But they don't create clones of the objects in the
arrays, they just copy the references, right?

 

[Gene Tani]

In Message-Id: <[email protected]>

array1 = [1,2,4,6]
array2 = [1,3,5,6]

array1 ?? array2 = [1,6] # Only add entries that occur in both arrays
array1 ?? array2 = [2,3,4,5] # Only add entries that occur in one of
both arrays

For former Array#& can be used if there're no duplicated elements in
your arrays. For latter, hmm, I can't remember no one methods but you
can (array1|array2)-(array1&array2), on same assumption.

Note these operators always make a new array for a result, they may
not be suitable when both your arrays are too large, though


--

be careful with ''&' and '-'
http://www.ruby-talk.org/cgi-bin/scat.rb/ruby/ruby-talk/65361

 

[YANAGAWA Kazuhisa]

In Message-Id: <[email protected]>

Hrm I don't really got this... Where do I have to put the references
(array1, array2) for this?

That's already answered by others so I don't repeat....

Thanks for the hint. But they don't create clones of the objects in the
arrays, they just copy the references, right?

That's right. By above saying I want to note on memory utilization
issue:

Since very_huge_array (operator) another_very_huge_array possibly
yields yet_another_very_huge_array, (a1|a2)-(a1&a2) can creates two
huge arrays which immediately discarded after the computation.