从Pandas DataFrame调用列数据时出现Python错误

Question

我正在练习将Google财经的股票市场数据导入Pandas DataFrame:

import pandas as pd
from pandas import Series

path = 'http://www.google.com/finance/historical?cid=542029859096076&startdate=Sep+22%2C+2001&enddate=Sep+20%2C+2016&num=30&ei=3HvhV4n3D8XGmAGp4q74Ag&output=csv'
df = pd.read_csv(path)

到目前为止一直很好,而且df还显示了我需要的完整数据集.

但是,在调用特定列时,例如

df['Date']

Python显示以下错误代码:

Traceback (most recent call last):

  File "<ipython-input-31-cb486dd31fbc>", line 1, in <module>
    df['Date']

  File "/Users/Username/anaconda/lib/python3.5/site-packages/pandas/core/frame.py", line 1997, in __getitem__
    return self._getitem_column(key)

  File "/Users/Username/anaconda/lib/python3.5/site-packages/pandas/core/frame.py", line 2004, in _getitem_column
    return self._get_item_cache(key)

  File "/Users/Username/anaconda/lib/python3.5/site-packages/pandas/core/generic.py", line 1350, in _get_item_cache
    values = self._data.get(item)

  File "/Users/Username/anaconda/lib/python3.5/site-packages/pandas/core/internals.py", line 3290, in get
    loc = self.items.get_loc(item)

  File "/Users/Username/anaconda/lib/python3.5/site-packages/pandas/indexes/base.py", line 1947, in get_loc
    return self._engine.get_loc(self._maybe_cast_indexer(key))

  File "pandas/index.pyx", line 137, in pandas.index.IndexEngine.get_loc (pandas/index.c:4154)

  File "pandas/index.pyx", line 159, in pandas.index.IndexEngine.get_loc (pandas/index.c:4018)

  File "pandas/hashtable.pyx", line 675, in pandas.hashtable.PyObjectHashTable.get_item (pandas/hashtable.c:12368)

  File "pandas/hashtable.pyx", line 683, in pandas.hashtable.PyObjectHashTable.get_item (pandas/hashtable.c:12322)

KeyError: 'Date'

另一方面,df ['High']等其他列也没问题.无论如何我可以解决这个问题吗？

Answer 1

此CSV文件包含BOM(字节顺序标记)签名,因此请尝试以下方式:

df = pd.read_csv(path, encoding='utf-8-sig')

如何轻松识别这个问题(感谢@ jezrael的提示):

In [11]: print(df.columns.tolist())
['\ufeffDate', 'Open', 'High', 'Low', 'Close', 'Volume']

并注意第一栏

注意:正如@ayhan注意到的那样,从版本0.19.0开始,Pandas会自动处理它:

pd.read_csv()中的错误导致BOM文件被错误地解析而不忽略BOM GH4793