Julia: does an Array contain a specific sub-array

Question

In julia we can check if an array contains a value, like so:

> 6 in [4,6,5]
true

However this returns false, when attempting to check for a sub-array in a specific order:

> [4,6] in [4,6,5]
false

What is the correct syntax to verify if a specific sub-array exists in an array?

Answer 1

I think it is worth mentioning that in Julia 1.0 you have the function issubset

> issubset([4,6], [4,6,5])
true

You can also quite conveniently call it using the \subseteq latex symbol

> [4,6] ⊆ [4,6,5]
true

This looks pretty optimized to me:

> using Random

> x, y = randperm(10^3)[1:10^2], randperm(10^3);

> @btime issubset(x, y);
16.153 μs (12 allocations: 45.96 KiB)

Answer 2

note that you can now vectorize in with a dot:

julia> in([4,6,5]).([4, 6])
2-element BitArray{1}:
 true
 true

and chain with all to get your answer:

julia> all(in([4,6,5]).([4, 6]))
true