IterTools product in Julia

Question

I would like to produce lists of 0 and 1 in Julia using IterTools. For example, in Python I can do:

for bits in itertools.product([0, 1], repeat=5):
    print(bits)

This will produce

(0, 0, 0, 0, 0)
(0, 0, 0, 0, 1)
(0, 0, 0, 1, 0)
(0, 0, 0, 1, 1)
(0, 0, 1, 0, 0)
(0, 0, 1, 0, 1)
(0, 0, 1, 1, 0)
...

I learned that in Julia there is similar functionality. Using IterTools, I can do:

for bits in product([0,1], [0,1])
    @show  bits
end

This will produce

(0,0)
(0,1)
...

The problem is that I need to hardcode the number of factors. For example, if I want bitstrings of length 5, I need to call product([0,1],[0,1],[0,1],[0,1],[0,1]).

I would like to know how to get arbitrary length lists using something similar to Python's repeat argument.

Answer 1

You can simply use the Iterators.repeated function to get a similar output to the Python function. You can set the n = 5 or any other value to get lists of arbitrary lengths.

julia> for bits in Iterators.product(Iterators.repeated((0, 1), 5)...)
           println(bits)
       end
(0, 0, 0, 0, 0)
(1, 0, 0, 0, 0)
(0, 1, 0, 0, 0)
(1, 1, 0, 0, 0)
(0, 0, 1, 0, 0)
(1, 0, 1, 0, 0)
...

Answer 2

You can achieve this in Julia by using the Iterators.product function and splatting a tuple of arrays. Here's a function to generate bitstrings of arbitrary length using the IterTools package:

using IterTools

function generate_bitstrings(length::Int)
    for bits in Iterators.product(ntuple(_ -> [0, 1], length)...)
        println(bits)
    end
end

generate_bitstrings(5)  

In this code, the ntuple function is used to create a tuple of arrays, each containing [0, 1]. The number of arrays in the tuple is equal to the desired bitstring length. Then, the splat operator ... is used to pass the arrays as separate arguments to the Iterators.product function, which generates the Cartesian product of the arrays, giving you the desired bitstrings.