Reordering an array based on its existence in another array

Question

a=[1,2,3,4,5]
b=[4,3]
array_wanted=[4,3,1,2,5]

I could do this via a mapping and pushing, but i would love to know more elegant ways of doing this.

Mladen Jablanović · Accepted Answer · 2011-01-13 08:33:34Z

6

(b & a) + (a - b)
# => [4, 3, 1, 2, 5]

And if you are sure that all elements from b are present in a, union operator | seems to return the proper order:

b | a
# => [4, 3, 1, 2, 5]

answered Jan 13, 2011 at 8:04

44.2k13 gold badges92 silver badges113 bronze badges

Sign up to request clarification or add additional context in comments.

1 Answer 1