如何通过具有单例尺寸的1d数组在python中索引没有单例尺寸的1d数组？

Question

what is the procedure to index variations of 1d arrays in python?

For example, consider the following example:

a = np.ones(100)
b = np.ones(100, 1)
a[b > 0]
IndexError                                Traceback (most recent call last)
<ipython-input-14-05e3ddce24c9> in <module>()
----> 1 a[b == 1]

IndexError: too many indices for array

How would I do this indexing, without creating a new array?

Answer 1

Only a is a 1D array. Singleton dimensions are still dimensions.

Remove the second dimension from b :

a[b[:, 0] > 0]

b[:, 0] takes a view of b 's data, not a copy.