[julia-users] Efficient way to split an array/dataframe?

[veryluckyxyz]

Hi,
I have an array of 100 elements. I want to split the array to 70 (test set) 
and 30 (train set) randomly.

N=100
A = rand(N);
n = convert(Int, ceil(N*0.7))
testindex = sample(1:size(A,1), replace=false,n)
testA = A[testindex];

How can I get the train set?

I could loop through testA and A to get trainA as below

trainA = Array(eltype(testA), N-n);
k=1
for elem in A
    if !(elem in testA)
        trainA[k] = elem
        k=k+1
    end
end

Is there a more efficient or elegant way to do this?

Thanks!