pandas 笔记

1.pandas 两列取最小值，如果其中一列为nan, 会取另外一列

>>> df3
   a  b    c
0  1  1  1.0
1  1  1  2.0
2  1  1  2.0
3  2  2  NaN
4  3  2  NaN
>>> df3['d'] = df3[['a', 'c']].min(axis=1)
>>> df3
   a  b    c    d
0  1  1  1.0  1.0
1  1  1  2.0  1.0
2  1  1  2.0  1.0
3  2  2  NaN  2.0
4  3  2  NaN  3.0
>>>