python - 读取DataFrame的列失败

Question

我正在使用 python 2.7 和 Anaconda2。当我将 txt 文件简单读取到数据帧中时 (df = pd.read_table("/home/testtab.txt",sep='\t',index_col=False))，然后读取其中一列如下 (df["col1"].head())，它给了我一个错误(见下文)。此外，行索引也存在，而我希望使用 index_col=False 禁用它。df.columns 的输出如下:

Index([u'col1', u'col2'],dtype='object')

错误:

KeyError                                  Traceback (most recent call last)
<ipython-input-3-c472f01c3482> in <module>()
----> 1 df["col1"].head()

/home/gooo/anaconda2/lib/python2.7/site-packages/pandas/core/frame.py in __getitem__(self, key)
   1995             return self._getitem_multilevel(key)
   1996         else:
-> 1997             return self._getitem_column(key)
   1998 
   1999     def _getitem_column(self, key):

/home/gooo/anaconda2/lib/python2.7/site-packages/pandas/core/frame.py in _getitem_column(self, key)
   2002         # get column
   2003         if self.columns.is_unique:
-> 2004             return self._get_item_cache(key)
   2005 
   2006         # duplicate columns & possible reduce dimensionality

/home/gooo/anaconda2/lib/python2.7/site-packages/pandas/core/generic.py in _get_item_cache(self, item)
   1348         res = cache.get(item)
   1349         if res is None:
-> 1350             values = self._data.get(item)
   1351             res = self._box_item_values(item, values)
   1352             cache[item] = res

/home/gooo/anaconda2/lib/python2.7/site-packages/pandas/core/internals.py in get(self, item, fastpath)
   3288 
   3289             if not isnull(item):
-> 3290                 loc = self.items.get_loc(item)
   3291             else:
   3292                 indexer = np.arange(len(self.items))[isnull(self.items)]

/home/gooo/anaconda2/lib/python2.7/site-packages/pandas/indexes/base.py in get_loc(self, key, method, tolerance)
   1945                 return self._engine.get_loc(key)
   1946             except KeyError:
-> 1947                 return self._engine.get_loc(self._maybe_cast_indexer(key))
   1948 
   1949         indexer = self.get_indexer([key], method=method, tolerance=tolerance)

pandas/index.pyx in pandas.index.IndexEngine.get_loc (pandas/index.c:4154)()

pandas/index.pyx in pandas.index.IndexEngine.get_loc (pandas/index.c:4018)()

pandas/hashtable.pyx in pandas.hashtable.PyObjectHashTable.get_item (pandas/hashtable.c:12368)()

pandas/hashtable.pyx in pandas.hashtable.PyObjectHashTable.get_item (pandas/hashtable.c:12322)()

KeyError: 'col1'

编辑:

df.info() 的输出:

<class 'pandas.core.frame.DataFrame'>
RangeIndex: 7499900 entries, 0 to 7499899
Data columns (total 18 columns):
col1       object
col2       float64
dtypes: float64(1), object(1)
memory usage: 1.0+ GB

Answer 1

pandas 版本 0.18.1 出现问题，升级到 0.19.1 后工作正常。

我认为可能是一些错误。