2022年 11月 5日

python中如何取非_python – 如何在numpy数组中获取非零值的位置?

>>> import numpy as np

>>>

>>> groupMatrix = np.array([

… [1, 1, 0, 0],

… [1, 0, 0, 0],

… [0, 0, 0, 2],

… [3, 3, 0, 2]

… ])

>>> np.nonzero(groupMatrix)

(array([0, 0, 1, 2, 3, 3, 3], dtype=int64), array([0, 1, 0, 3, 0, 1, 3], dtype=int64))

>>> zip(np.nonzero(groupMatrix))

[(array([0, 0, 1, 2, 3, 3, 3], dtype=int64),), (array([0, 1, 0, 3, 0, 1, 3], dtype=int64),)]

使用zip(* …):

>>> zip(*np.nonzero(groupMatrix))

[(0, 0), (0, 1), (1, 0), (2, 3), (3, 0), (3, 1), (3, 3)]

zip(* a)就像zip(a [0],a [1],…)

>>> a = [(0, 1, 2), (3, 4, 5)]

>>> zip(a)

[((0, 1, 2),), ((3, 4, 5),)]

>>> zip(a[0], a[1])

[(0, 3), (1, 4), (2, 5)]

>>> zip(*a)

[(0, 3), (1, 4), (2, 5)]