scipy.special.comb¶
-
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
If exact is False, then floating point precision is used, otherwise exact long integer is computed.
- 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 ufunc
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 comb >>> k = np.array([3, 4]) >>> n = np.array([10, 10]) >>> comb(n, k, exact=False) array([ 120., 210.]) >>> comb(10, 3, exact=True) 120L >>> comb(10, 3, exact=True, repetition=True) 220L