Question

我正在尝试一个简单的代码，但是它抛出了一个错误

import pandas as pd

df = pd.read_csv('AshokLeyland.csv')

print(df.head())

df = df[['Open Price','Close Price']]

错误

df = df[['Open Price','Close Price']]
Traceback (most recent call last):

  File "<ipython-input-5-33b1f1145780>", line 1, in <module>
    df = df[['Open Price','Close Price']]

  File "C:\Users\gg\Anaconda3\lib\site-packages\pandas\core\frame.py", line 1958, in __getitem__
    return self._getitem_array(key)

  File "C:\Users\gg\Anaconda3\lib\site-packages\pandas\core\frame.py", line 2002, in _getitem_array
    indexer = self.loc._convert_to_indexer(key, axis=1)

  File "C:\Users\gg\Anaconda3\lib\site-packages\pandas\core\indexing.py", line 1231, in _convert_to_indexer
    raise KeyError('%s not in index' % objarr[mask])

KeyError: "['Open Price' 'Close Price'] not in index"

我无法附加文件，但示例输出如下：-

print(df.head())
        Date     Symbol  Series   Open Price   High Price   Low Price  \
0  06-Nov-18   ASHOKLEY      EQ       121.35       122.15      118.70   
1  05-Nov-18   ASHOKLEY      EQ       117.65       121.85      116.20   
2  02-Nov-18   ASHOKLEY      EQ       114.40       118.45      113.80   
3  01-Nov-18   ASHOKLEY      EQ       115.50       116.85      112.35   
4  31-Oct-18   ASHOKLEY      EQ       115.00       115.90      112.20 

print(df.columns.tolist())
['Date', ' Symbol', ' Series', ' Open Price', ' High Price', ' Low Price', ' Last Traded Price ', ' Close Price', ' Total Traded Quantity', ' Turnover (in Lakhs)']

不确定是什么问题。我只想用一些选定的列创建一个新的df。

Answer 1

问题列名称中有多余的空格。

df = df[[' Open Price',' Close Price',' Low Price',' Close Price',' Total Traded Quantity']]

这解决了问题

Answer 2

import pandas as pd

df=pd.DataFrame([
    ['06-Nov-18','ASHOKLEY','EQ','121.35','122.15','118.70'],
    ['05-Nov-18','ASHOKLEY','EQ','117.65','121.85','116.20'],
    ['02-Nov-18','ASHOKLEY','EQ','114.40','118.45','113.80'],
    ['01-Nov-18','ASHOKLEY','EQ','115.50','116.85','112.35'],
    ['31-Oct-18','ASHOKLEY','EQ','115.00','115.90','112.20']],  
     columns=['Date','Symbol','Series','Open Price','High Price','Low Price'])

df

    Date    Symbol  Series  Open Price  High Price  Low Price
0   06-Nov-18   ASHOKLEY    EQ  121.35  122.15  118.70
1   05-Nov-18   ASHOKLEY    EQ  117.65  121.85  116.20
2   02-Nov-18   ASHOKLEY    EQ  114.40  118.45  113.80
3   01-Nov-18   ASHOKLEY    EQ  115.50  116.85  112.35
4   31-Oct-18   ASHOKLEY    EQ  115.00  115.90  112.20

df[['Symbol','Open Price']]

    Symbol  Open Price
0   ASHOKLEY    121.35
1   ASHOKLEY    117.65
2   ASHOKLEY    114.40
3   ASHOKLEY    115.50
4   ASHOKLEY    115.00

它在这里工作。问题一定是在csv读取期间。注意每个列名称前的空格。字符串必须相同。

创建一个新的Pandas DataFrame

2 个答案: