从数组中删除元素 [英] Deleting Elements from an array

问题描述

我有一个numpy数组，我想删除该数组的前3个元素.我尝试了这种解决方案:

I have a numpy array and I want to delete the first 3 elements of the array. I tried this solution:

           a = np.arange(0,10)
           i=0
           while(i<3):
             del a[0]
             i=i+1

这给我一个错误，提示" ValueError:无法删除数组元素".我不明白为什么会这样.感谢您的帮助！

This gives me an error that "ValueError: cannot delete array elements". I do not understand why this is the case. i'd appreciate the help thanks!

推荐答案

Numpy数组的大小是固定的，因此不能简单地从其中删除元素.实现所需目标的最简单方法是使用切片:

Numpy arrays have a fixed size, hence you cannot simply delete an element from them. The simplest way to achieve what you want is to use slicing:

a = a[3:]

这将从原始数组的第4个元素开始创建一个新数组.

This will create a new array starting with the 4th element of the original array.

在某些情况下，切片仅仅是不够的.如果要创建由原始数组中的特定元素组成的子数组，则可以使用另一个数组来选择索引:

For certain scenarios, slicing is just not enough. If you want to create a subarray consisting of specific elements from the original array, you can use another array to select the indices:

>>> a = arange(10, 20)
>>> a[[1, 4, 5]]
array([11, 14, 15])

因此，基本上，a[[1,4,5]]将返回一个由原始数组的元素1,4和5组成的数组.

So basically, a[[1,4,5]] will return an array that consists of the elements 1,4 and 5 of the original array.

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