list.pop 的 numpy 等效项?
问题描述
是否有一个 numpy 方法等效于 python 列表的内置 pop 方法?
Is there a numpy method which is equivalent to the builtin pop for python lists?
Popping 显然不适用于 numpy 数组，我想避免列表转换.
Popping obviously doesn't work on numpy arrays, and I want to avoid a list conversion.
解决方案
NumPy 数组没有 pop 方法，但你可以只使用基本切片(这会很有效，因为它返回一个视图，而不是副本):
There is no pop method for NumPy arrays, but you could just use basic slicing (which would be efficient since it returns a view, not a copy):
In [104]: y = np.arange(5); y
Out[105]: array([0, 1, 2, 3, 4])
In [106]: last, y = y[-1], y[:-1]
In [107]: last, y
Out[107]: (4, array([0, 1, 2, 3]))
如果有 pop 方法，它将返回 y 中的 last 值并修改 y.
If there were a pop method it would return the last value in y and modify y.
以上，
last, y = y[-1], y[:-1]
将最后一个值赋给变量last并修改y.
assigns the last value to the variable last and modifies y.
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