scipy.special.perm¶
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scipy.special.perm(N, k, exact=False)[source]¶ Permutations of N things taken k at a time, i.e., k-permutations of N.
It’s also known as “partial permutations”.
- Parameters
- Nint, ndarray
Number of things.
- kint, ndarray
Number of elements taken.
- exactbool, optional
If exact is False, then floating point precision is used, otherwise exact long integer is computed.
- Returns
- valint, ndarray
The number of k-permutations of N.
Notes
Array arguments accepted only for exact=False case.
If k > N, N < 0, or k < 0, then a 0 is returned.
Examples
>>> from scipy.special import perm >>> k = np.array([3, 4]) >>> n = np.array([10, 10]) >>> perm(n, k) array([ 720., 5040.]) >>> perm(10, 3, exact=True) 720