carl_pch carl_pch - 1 year ago 201
Python Question

Python error when calling column data from Pandas DataFrame

I was practicing to import stock market data from Google Finance into a Pandas DataFrame:

import pandas as pd
from pandas import Series

path = ''
df = pd.read_csv(path)

So far so good, and df also shows the complete data set I need.

However, when calling particular columns, like


Python shows the error codes below:

Traceback (most recent call last):

File "<ipython-input-31-cb486dd31fbc>", line 1, in <module>

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

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

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

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

File "/Users/Username/anaconda/lib/python3.5/site-packages/pandas/indexes/", 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'

On the other hand, other columns such as df['High'] turns out to be okay. Is there anyway I can fix this issue?

Answer Source

this CSV file contains BOM (Byte Order Mark) signature, so try it this way:

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

How one can easily identify this problem (thanks to @jezrael's hint):

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

and pay attention at the first column

NOTE: as @ayhan has noticed, starting with version 0.19.0 Pandas will take care of it automatically:

Bug in pd.read_csv() which caused BOM files to be incorrectly parsed by not ignoring the BOM GH4793

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