How to generate random integers by group in julia - julia

Question

First, I would like to divide the intergers from 1 to n equally into m groups.
Second, I want to generate random intergers without replacement in each group by Julia.
Third, I would like to combine all the random integers.
For example, n=10000, m=2. Then the julia code would be
using Distributions
n=10000
order1 = sample(1:5000, 5000, replace = false)
order2 = sample(5001:10000, 5000, replace = false)
order=[order1;order2]
For example, n=10000, m=5. Then the julia code would be
using Distributions
n=10000
order1 = sample(1:2000, 2000, replace = false)
order2 = sample(2001:4000, 2000, replace = false)
order3 = sample(4001:6000, 2000, replace = false)
order4 = sample(6001:8000, 2000, replace = false)
order5 = sample(8001:10000, 2000, replace = false)
order=[order1;order2;order3;order4;order5]
I am just wondering if I can improve the julia code above. If m=100. then my code will be extremely long. There must be an eaiser way to do this.

Answer 1

Assume that you have eg. n=30 and m=5 (note that n % m == 0).
Than you can create the place to hold the results named x:
x = collect(1:n);
And now you can do this one liner (this requires using Random):
shuffle!.(eachcol(reshape(x, n ÷ m, m)));
Let us see the result (you have 5 groups and within each group values are randomly ordered without repetitions):
julia> x'
1×30 adjoint(::Vector{Int64}) with eltype Int64:
1 5 3 2 4 6 12 10 8 9 7 11 16 18 13 14 15 17 24 21 23 22 20 19 26 25 27 30 29 28