comb — SciPy v1.15.2 Manual (original) (raw)

scipy.special.

scipy.special.comb(N, k, *, exact=False, repetition=False)[source]#

The number of combinations of N things taken k at a time.

This is often expressed as “N choose k”.

Parameters:

Nint, ndarray

Number of things.

kint, ndarray

Number of elements taken.

exactbool, optional

For integers, if exact is False, then floating point precision is used, otherwise the result is computed exactly.

Deprecated since version 1.14.0: exact=True is deprecated for non-integer N and k and will raise an error in SciPy 1.16.0

repetitionbool, optional

If repetition is True, then the number of combinations with repetition is computed.

Returns:

valint, float, ndarray

The total number of combinations.

See also

binom

Binomial coefficient considered as a function of two real variables.

Notes

• Array arguments accepted only for exact=False case.
• If N < 0, or k < 0, then 0 is returned.
• If k > N and repetition=False, then 0 is returned.

Examples

import numpy as np from scipy.special import comb k = np.array([3, 4]) n = np.array([10, 10]) comb(n, k, exact=False) array([ 120., 210.]) comb(10, 3, exact=True) 120 comb(10, 3, exact=True, repetition=True) 220