NumPy参考 >通用功能(ufunc) > numpy.ufunc.outer
method
ufunc.
outer
(A, B, **kwargs)¶Apply the ufunc op to all pairs (a, b) with a in A and b in B.
Let M = A.ndim
, N = B.ndim
. Then the result, C, of
op.outer(A, B)
is an array of dimension M + N such that:
For A and B one-dimensional, this is equivalent to:
r = empty(len(A),len(B))
for i in range(len(A)):
for j in range(len(B)):
r[i,j] = op(A[i], B[j]) # op = ufunc in question
First array
Second array
Arguments to pass on to the ufunc. Typically dtype
or out.
Output array
See also
Examples
>>> np.multiply.outer([1, 2, 3], [4, 5, 6])
array([[ 4, 5, 6],
[ 8, 10, 12],
[12, 15, 18]])
A multi-dimensional example:
>>> A = np.array([[1, 2, 3], [4, 5, 6]])
>>> A.shape
(2, 3)
>>> B = np.array([[1, 2, 3, 4]])
>>> B.shape
(1, 4)
>>> C = np.multiply.outer(A, B)
>>> C.shape; C
(2, 3, 1, 4)
array([[[[ 1, 2, 3, 4]],
[[ 2, 4, 6, 8]],
[[ 3, 6, 9, 12]]],
[[[ 4, 8, 12, 16]],
[[ 5, 10, 15, 20]],
[[ 6, 12, 18, 24]]]])