I am trying to convert a python script to Julia. I am checking to make sure I am doing this code in the most optimal way. Please see the following code:
julia> a = [1,2,3,4,5]
5-element Array{Int64,1}:
1
2
3
4
5
julia> if 1 in a
print("1 is in a")
end
1 is in a
julia> if 6 not in a
print("6 not in a")
end
ERROR: TypeError: non-boolean (Int64) used in boolean context
Stacktrace:
[1] top-level scope at REPL[6]:1
julia> push!(a, 6)
6-element Array{Int64,1}:
1
2
3
4
5
6
julia> if (6 in a) == true
print("6 in a")
end
6 not in a
julia> b = [1]
1-element Array{Int64,1}:
1
julia> if (6 in b) == true
print("6 in b")
end
Am I doing this "not in" check correctly?
julia> a = [1, 2, 3, 4, 5];
julia> 6 ∉ a
true
The ∉ symbol can be typed in the REPL by typing \notin and then hitting TAB. Of course, the ∈ symbol is also available as an alternative to in by typing \in and hitting TAB:
julia> 6 ∈ a
false
Sometimes you need a vectorized version:
julia> x = [2, 7];
julia> x .∉ Ref(a)
2-element BitArray{1}:
0
1
The Ref is needed in this case so that a is treated as a scalar in the broadcasting operation.
If you prefer to avoid Unicode characters, you can write !(6 in a) instead of 6 ∉ a.