创建具有连续整数但忽略特定数字的numpy数组的最快方法

Question

I need to generate a numpy array fill with consecutive numbers but ignore a specific number.

For example, I need a numpy array between 0 to 5 but ignore 3. The result will be [0,1,2,4,5,] .

My current solution is very slow when the array size I need is large. Here is my testing code and it took 2m34s on my i7-6770 machine with Python 3.6.5 .

import numpy as np

length = 150000

for _ in range(10000):
    skip = np.random.randint(length)
    indexing = np.asarray([i for i in range(length) if i != skip])

Hence, I would like to know if there's better one. Thanks

Answer 1

Instead of ignoring a number, split your array into two ranges, leaving the number you're ignoring out. Then use np.arange to make the arrays and concatenate them.

def range_with_ignore(start, stop, ignore):
    return np.concatenate([
        np.arange(start, ignore),
        np.arange(ignore + 1, stop)
    ])