Split A List Into N Randomly Sized Chunks

I am trying to split a list into n sublists where the size of each sublist is random (with at least one entry; assume P>I). I used numpy.split function which works fine but does

Solution 1:

The problem can be refactored as choosing I-1 random split points from {1,2,...,P-1}, which can be viewed using stars and bars.

Therefore, it can be implemented as follows:

import numpy as np

split_points = np.random.choice(P - 2, I - 1, replace=False) + 1
split_points.sort()
result = np.split(data, split_points)

Solution 2:

np.split is still the way to go. If you pass in a sequence of integers, split will treat them as cut points. Generating random cut points is easy. You can do something like

P = 10I = 5data = np.arange(P) + 1indices = np.random.randint(P, size=I - 1)

You want I - 1 cut points to get I chunks. The indices need to be sorted, and duplicates need to be removed. np.unique does both for you. You may end up with fewer than I chunks this way:

result = np.split(data, indices)

If you absolutely need to have I numbers, choose without resampling. That can be implemented for example via np.shuffle:

indices = np.arange(1, P)
np.random.shuffle(indices)
indices = indices[:I - 1]
indices.sort()