KeyError:“[['col label 1','col label 2']]都不在[列]中”

我正在尝试使用 .loc . 根据熊猫文献, https://pandas.pydata.org/pandas-docs/stable/user_guide/indexing.html , loc先生 似乎是用例的正确索引器。

原始数据帧和带标签的列是否存在:

列标签是动态构造的,并作为列表传递给数据帧切片。

# Create dictionaries 
prop_dict = dict(zip(df_list.id, df_list.Company))
city_dict = dict(zip(df_list.id, df_list.city))   

# Lookup keys (property ids) from prop_dict
propKeys = getKeysByValue(prop_dict, landlord)
cityKeys = getKeysByValue(city_dict, market)

prop_list = list(set(propKeys) & set(cityKeys))
print(prop_list)

[19, 27]

# Slice dataframe 
df_temp = df_t.loc[:, prop_list]

但是,这会抛出一个错误 KeyError: 'None of [[19, 27]] are in the [columns]'

Traceback (most recent call last):
  File "/Platform/Deploy/tabs/market.py", line 279, in render_table
    result = top_leads(company, market)
  File "/Platform/Deploy/return_leads.py", line 86, in top_leads
    df_temp = df_matrix.loc[:, prop_list]
  File "/anaconda3/lib/python3.7/site-packages/pandas/core/indexing.py", line 1472, in __getitem__
    return self._getitem_tuple(key)
  File "/anaconda3/lib/python3.7/site-packages/pandas/core/indexing.py", line 890, in _getitem_tuple
    retval = getattr(retval, self.name)._getitem_axis(key, axis=i)
  File "/anaconda3/lib/python3.7/site-packages/pandas/core/indexing.py", line 1901, in _getitem_axis
    return self._getitem_iterable(key, axis=axis)
  File "/anaconda3/lib/python3.7/site-packages/pandas/core/indexing.py", line 1143, in _getitem_iterable
    self._validate_read_indexer(key, indexer, axis)
  File "/anaconda3/lib/python3.7/site-packages/pandas/core/indexing.py", line 1206, in _validate_read_indexer
    key=key, axis=self.obj._get_axis_name(axis)))
KeyError: 'None of [[19, 27]] are in the [columns]'