python - numpy.extract 和 numpy.any 函数，是否可以使其更简单？

Question

如果有任何可能使此代码更简单，我将不胜感激！我试图摆脱零的行。第一列是日期。如果所有其他列都为零，则必须删除它们。列数不同。

import numpy as np

condition = [ np.any( list(x)[1:] ) for x in r]
r = np.extract( condition, r )

numpy.extract文档

Answer 1

You can avoid the list comprehension and instead use fancy indexing:

#!/usr/bin/env python
import numpy as np
import datetime
r=np.array([(datetime.date(2000,1,1),0,1),
            (datetime.date(2000,1,1),1,1),
            (datetime.date(2000,1,1),1,0),
            (datetime.date(2000,1,1),0,0),                        
            ])
r=r[r[:,1:].any(axis=1)]
print(r)
# [[2000-01-01 0 1]
#  [2000-01-01 1 1]
#  [2000-01-01 1 0]

if r is an ndarray, then r[:,1:] is a view with the first column removed. r[:,1:].any(axis=1) is a boolean array, which you can then use as a "fancy index"