擅长:python、mysql、java
<pre><code>In [1]: import numpy as np
In [2]: k = 2
In [3]: i, j = np.ogrid[0:5,0:5]
In [4]: mask = (j-i-k < 0)
In [5]: mask
Out[5]:
array([[ True, True, False, False, False],
[ True, True, True, False, False],
[ True, True, True, True, False],
[ True, True, True, True, True],
[ True, True, True, True, True]], dtype=bool)
In [6]: mask.shape
Out[6]: (5, 5)
In [7]: mask.dtype
Out[7]: dtype('bool')
</code></pre>