Scalar contained by vector of StaticArrays

New to Julia
1

Hi!
I want to check if an integer is contained by a vector of StaticArrays. Here’s an example (with regular arrays, but it’s the same issue).

a = [[1,2], [3,4]]
1 in a # false

I guess I could write a for loop, but that’s not very elegant.
Notes:

  • The number I’m looking for will always be in the first “column” (i.e., first position of a subarray).
  • If the number is in a, I will need to find it’s position, something like this: findfirst(x->x==1,a), which doesn’t work in this case either.

Thanks a lot!
PS: this is a silly question, but a difficult one to Google. The word “in” is a bit too common.

2 
julia> any(∋(1), a)
true

julia> findfirst(∋(1), a)
1

note: this only handles one level of nest-ness

1 Like
3

That doesn’t seem to work for me.

julia> any(∋(1), a)
ERROR: MethodError: no method matching ∋(::Int64)
Closest candidates are:
  ∋(::Any, ::Any) at operators.jl:1069
Stacktrace:
 [1] top-level scope at REPL[14]:1

I’m also having some trouble with the ∋ character. Launching Julia in Windows it looks like a square with a question mark in the middle, while in Linux and in VS Code it does appear. Does this function have another name?
I’m using Julia Version 1.5.3.
Thanks!

4

yeah got added “recentlly”
https://github.com/JuliaLang/julia/pull/38475

5

In the meantime you can use any(v -> 1 ∈ v, a)

6

Thank you both!
For now:

any(v -> 1 ∈ v, a)
findfirst(v -> 1 ∈ v, a)

Works for me!

1 Like