pythonindex out of bounds_Pandas Dataframe 的 out of bounds 问题

necomancer

2018-12-26 09:44:10 +08:00

用 get()，如果列有名字则用名字，否则用序号，get 如果没有则返回 None，方便处理。

In [2]: import pandas as pd

In [3]: df = pd.DataFrame(np.random.randn(8, 4))

In [4]: df

Out[4]:

0 1 2 3

0 -0.727670 -0.182557 -0.957270 -0.153352

1 -0.340649 -0.313155 -1.219515 0.082472

2 0.023527 0.496896 0.443117 -0.391405

3 -0.522745 0.879736 -1.358356 0.177883

4 -0.314936 -1.795936 -1.510872 1.039757

5 0.000243 -0.826999 -0.365514 -0.907249

6 0.058694 -0.521912 -0.863121 0.842308

7 0.846951 0.325337 -0.821745 0.111492

In [5]: df.get(0)

Out[5]:

0 -0.727670

1 -0.340649

2 0.023527

3 -0.522745

4 -0.314936

5 0.000243

6 0.058694

7 0.846951

Name: 0, dtype: float64

In [6]: df.get(1)

Out[6]:

0 -0.182557

1 -0.313155

2 0.496896

3 0.879736

4 -1.795936

5 -0.826999

6 -0.521912

7 0.325337

Name: 1, dtype: float64

In [7]: df.get(3)

Out[7]:

0 -0.153352

1 0.082472

2 -0.391405

3 0.177883

4 1.039757

5 -0.907249

6 0.842308

7 0.111492

Name: 3, dtype: float64

In [8]: df.get(4)

In [9]:

或者列有名字：

In [10]: df = pd.DataFrame(np.random.randn(8, 4), columns=['A', 'B', 'C', 'D'])

In [11]: df

Out[11]:

A B C D

0 -1.521750 -0.704144 -0.565343 -0.389537

1 -0.634391 0.672338 0.857965 0.294724

2 -0.764034 0.907585 -1.454368 -0.637835

3 -1.218633 -1.473434 1.441891 1.554465

4 -1.100643 -2.303968 -1.788275 -0.382192

5 1.476041 -0.735864 -0.359389 0.896467

6 1.662332 -0.944238 0.308855 -0.013283

7 1.357332 0.529256 1.169877 0.745932

In [12]: df.get('E')

In [13]: df.get('B')

Out[13]:

0 -0.704144

1 0.672338

2 0.907585

3 -1.473434

4 -2.303968

5 -0.735864

6 -0.944238

7 0.529256

Name: B, dtype: float64

实在不行还可以用 try except 吧。