如何从向量中删除数字? [英] How to delete numbers from a vector?

问题描述

我有这个向量

v = (1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,18,19,20)

我想删除2和3的倍数.我该怎么做?

I want to remove the multiples of 2 and 3. How would I do this?

我试图这样做，但是我没有用:

I tried to do this but I doesn't work:

import numpy as np
V = (1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,18,19,20)
Mul3 = np.arange(1,21,3)
Mul2 = np.arange(1,21,2)
V1 = V [-mul2]
V2 = V1 [-mul3]

推荐答案

鉴于您已经在使用NumPy，则可以使用

Given that you use NumPy already you can use boolean array indexing to remove the multiples of 2 and 3:

>>> import numpy as np
>>> v = (1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,18,19,20)  # that's a tuple
>>> arr = np.array(v)  # convert the tuple to a numpy array
>>> arr[(arr % 2 != 0) & (arr % 3 != 0)]
array([ 1,  5,  7, 11, 13, 19])

(arr % 2 != 0)创建一个布尔掩码，其中2的倍数是False，其他所有元素True以及(arr % 3 != 0)都适用于3的倍数.这两个遮罩使用&(和)组合在一起，然后用作arr

The (arr % 2 != 0) creates a boolean mask where multiples of 2 are False and everything else True and likewise the (arr % 3 != 0) works for multiples of 3. These two masks are combined using & (and) and then used as mask for your arr

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