Question

我在熊猫中有一个数据框，如下所示：

   100  200  300  400
0    1    1    0    1
1    1    1    1    0

我要做的是从此数据框中选择特定的列。但是，当我尝试以下代码时（df_matrix是顶部显示的数据框）：

intermediary_df = df_matrix["100"]

它不起作用，据我所知是因为它是整数。我尝试用str（100）强制执行此操作，但给出了与以前相同的错误：

File "pandas\_libs\hashtable_class_helper.pxi", line 958, in pandas._libs.hashtable.Int64HashTable.get_item
TypeError: an integer is required

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "A:\python project\venv\lib\site-packages\pandas\core\indexes\base.py", line 3078, in get_loc
    return self._engine.get_loc(key)
  File "pandas\_libs\index.pyx", line 140, in pandas._libs.index.IndexEngine.get_loc
  File "pandas\_libs\index.pyx", line 164, in pandas._libs.index.IndexEngine.get_loc
KeyError: '100'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "pandas\_libs\index.pyx", line 162, in pandas._libs.index.IndexEngine.get_loc
  File "pandas\_libs\hashtable_class_helper.pxi", line 958, in pandas._libs.hashtable.Int64HashTable.get_item
TypeError: an integer is required

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "A:/python project/testing/testing4.py", line 42, in <module>
    intermediary_df = df_matrix["100"]
  File "A:\python project\venv\lib\site-packages\pandas\core\frame.py", line 2688, in __getitem__
    return self._getitem_column(key)
  File "A:\python project\venv\lib\site-packages\pandas\core\frame.py", line 2695, in _getitem_column
    return self._get_item_cache(key)
  File "A:\python project\venv\lib\site-packages\pandas\core\generic.py", line 2489, in _get_item_cache
    values = self._data.get(item)
  File "A:\python project\venv\lib\site-packages\pandas\core\internals.py", line 4115, in get
    loc = self.items.get_loc(item)
  File "A:\python project\venv\lib\site-packages\pandas\core\indexes\base.py", line 3080, in get_loc
    return self._engine.get_loc(self._maybe_cast_indexer(key))
  File "pandas\_libs\index.pyx", line 140, in pandas._libs.index.IndexEngine.get_loc
  File "pandas\_libs\index.pyx", line 164, in pandas._libs.index.IndexEngine.get_loc
KeyError: '100'

有人知道如何解决这个问题吗？谢谢！

编辑1：

尝试使用intermediary_df = df_matrix[100]后，它按预期工作。顺便说一句，如果其他人遇到此问题并想同时选择多个列，则可以使用：

intermediary_df = df_matrix[[100, 300]]

，输出将是：

   100  300
0    1    0
1    1    1

Answer 1

我认为您的列类型是整数，但是如果没有尝试使用DataFrame.loc

示例：

intermediary_df = df_matrix.loc[:,100]

或

intermediary_df = df_matrix.iloc[:,0]

Answer 2

由于您的列是int，因此在这种情况下只需使用以下内容。

intermediary_df = df_matrix[100]`

如果您希望以str的方式访问列，请使用：

df.columns = [str(x) for x in df.columns]

然后

df['100']

输出

0    1
1    1
Name: 100, dtype: int64

选择熊猫数据框中具有整数标题的列

2 个答案: