为什么这个切片示例不能给出与标准列表相同的结果?它的工作原理就像它首先计算an[:2] = bn[:2]
,然后再计算bn[:2] = an[:2]
。你知道吗
import numpy as np
l1 = [1, 2, 3]
l2 = [4, 5, 6]
a = list(l1)
b = list(l2)
an = np.array(a)
bn = np.array(b)
print(a, b)
a[:2], b[:2] = b[:2], a[:2]
print(a, b)
print(an, bn)
an[:2], bn[:2] = bn[:2], an[:2]
print(an, bn)
输出:
--------------------
[1, 2, 3] [4, 5, 6]
[4, 5, 3] [1, 2, 6]
--------------------
[1 2 3] [4 5 6]
[4 5 3] [4 5 6]
--------------------
如果我这样做-一切正常:
dummy = an[:2]
an[:2] = bn[:2]
bn[:2] = dummy
对于列表
a[:2]
是包含前两个元素的列表的副本,对于numpy数组,这只是一个引用。 您需要制作一份副本,明确地:相关问题 更多 >
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