Random! Shuffle v.s. Permutation (Numpy)

Generally, in Numpy, both random.permutation and random.shuffle randomly shuffle elements in an array. But there are differences:

Difference:

np.random.permutation has two differences from np.random.shuffle:

if passed an array, it will return a shuffled copy of the array; np.random.shuffle shuffles the array inplace

if passed an integer, it will return a shuffled range i.e. np.random.shuffle(np.arange(n))

If x is an integer, randomly permute np.arange(x). If x is an array, make a copy and shuffle the elements randomly.

The source code might help to understand this:

3280        def permutation(self, object x):
...
3307            if isinstance(x, (int, np.integer)):
3308                arr = np.arange(x)
3309            else:
3310                arr = np.array(x)
3311            self.shuffle(arr)
3312            return arr

Reference

» shuffle vs permute numpy - Stack Overflow

KF