Ruby: Compare if array contains other array [duplicate]

Question

how can i compare if an array of strings contains a smaller array of strings in Ruby?

e.g.

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

now i want to check if a contains b and get true/false

Thanks.

you can check by (a & b) == b, it will return boolean value true / false — Gagan Gami
– Gagan Gami, Commented Aug 10, 2018 at 10:33
@GaganGami nope, this is not correct; & squeezes duplicates resulting in weird [1, 1] & [1, 1] == [1, 1] #⇒ false because surprisingly [1, 1] & [1, 1] == [1]. — Aleksei Matiushkin
– Aleksei Matiushkin, Commented Aug 10, 2018 at 10:51

Aleksei Matiushkin · Accepted Answer · 2018-08-09 12:20:43Z

0

The most common approach would be to

(b - a).empty?

It has issues with unique elements, though. To detect whether a includes all elements from b, one should:

a_copy = a.dup
b.all? { |e| a_copy.delete e }
# or
b.all?(&a_copy.method(:delete))

answered Aug 9, 2018 at 12:20

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3 Comments

Thanks, I solved it with b.all? { |x| a.include(x) }

@EnginTopuzoglu once again, it won’t work if arrays might contain duplicates.

I see, thanks, they dont contain duplicates but they might, so i changed it to your code, still working