In Julia (julialang.org) if you are rather interested in finding the indices (indexes) of the elements in an array that fulfils a certain boolean condition then find is your friend, like so:
julia> probs = [0.1, 0.2, 0.3, 0.4, 0.5]
5-element Array{Float64,1}:
0.1
0.2
0.3
0.4
0.5
julia> find(x->x>0.2, probs)
3-element Array{Int64,1}:
3
4
5