！/ usr / bin / env python3

Question

我正在尝试使用pd.merge合并两个数据帧。如果两个数据框中都存在公司名称，我想从数据框2添加“电话”列。每次我运行代码时，即使这是我要合并的列名，我也会得到KeyError ='Company'。

我尝试过的事情：

pd.merge(northstar,julie['Phone'], on='Company')
northstar.merge(julie['Phone'], on 'Company')
pd.merge('Company','Title','First Name','Last Name','Address1','Address2','City','State','Zip','Mail Stop','Industry','Service1','Service2','Service3','Service4','P2','Fax or Ext.','Email','Secondary Contact','Secondary Email','Call Appt','Notes'],julie['Phone'],on='Company')

我得到KeyError='Company' everytime.

！/ usr / bin / env python3

标准库

import pandas as pd


northstar= pd.read_csv('/home/amypeiper/Downloads/northstar_dw_2018_q12019.csv')

                           Company                  Title  ...      Call Appt Notes
0                 24M TECHNOLOGIES          MECH ENGINEER  ...            NaN   NaN
1                   3D SYSTEMS INC          COMMODITY MGR  ...            NaN   NaN
2                               3M                    ENG  ...            NaN   NaN
3                        A & E INC              PROD ENGR  ...            NaN   NaN
4        A. W.  CHESTERTON COMPANY        PROCUREMENT MGR  ...            NaN   NaN
5                              ABB        SR MFG ENGINEER  ...            NaN   NaN
6              ABBOTT LABORATORIES       CALIBRATION ENGR  ...            NaN   NaN
7                ABBOTT MACHINE CO        BUYER/DRAFTSMAN  ...            NaN   NaN

julie= pd.read_csv('/home/amypeiper/Downloads/from_julie.csv')

[1457 rows x 24 columns]
                           company                  Title  ... Service4 Priority
0                 24M TECHNOLOGIES          MECH ENGINEER  ...       99      NaN
1                               3M                    ENG  ...       95      NaN
2                    4D DESIGN LLC        DESIGN ENGINEER  ...       37      NaN
3                        A & E INC              PROD ENGR  ...       41      NaN
4                              ABB        SR MFG ENGINEER  ...       52      NaN

northstar['Company'].isin(julie['Company']).value_counts()

result = pd.merge(northstar['Company','Title','First Name','Last Name','Address1',
                            'Address2','City','State','Zip','Mail Stop','Industry','Service1','Service2','Service3','Service4',
                            'P2','Fax or Ext.','Email','Secondary Contact','Secondary Email','Call Appt','Notes'],julie['Phone'],on='Company')

我希望得到一个数据框名称结果，该结果包含来自northstar数据框的所有列以及来自julie数据框的“电话”列。我一直收到同样的错误：

Traceback (most recent call last):

  File "<ipython-input-11-e230d033a0e2>", line 8, in <module>
    northstar['Company'].isin(julie['Company']).value_counts()

  File "/home/amypeiper/anaconda3/lib/python3.7/site-packages/pandas/core/frame.py", line 2927, in __getitem__
    indexer = self.columns.get_loc(key)

  File "/home/amypeiper/anaconda3/lib/python3.7/site-packages/pandas/core/indexes/base.py", line 2659, in get_loc
    return self._engine.get_loc(self._maybe_cast_indexer(key))

  File "pandas/_libs/index.pyx", line 108, in pandas._libs.index.IndexEngine.get_loc

  File "pandas/_libs/index.pyx", line 132, in pandas._libs.index.IndexEngine.get_loc

  File "pandas/_libs/hashtable_class_helper.pxi", line 1601, in pandas._libs.hashtable.PyObjectHashTable.get_item

  File "pandas/_libs/hashtable_class_helper.pxi", line 1608, in pandas._libs.hashtable.PyObjectHashTable.get_item

KeyError: 'Company'

Answer 1

juilie['Phone']仅给您Phone中的julie列。您还需要包括Company列：

pd.merge(northstar, julie[['Phone','Company']]), on='Company')

Answer 2

如果您想在 Company 列上进行合并，则涉及到两者 DataFrame必须具有此列。

因此合并应类似于：

pd.merge(northstar['Company', ...], julie['Company', 'Phone'], on='Company',
    how='left')

请注意，默认合并模式（ how ）是 inner 。你必须改变它，否则结果将只包含两个DataFrame中都存在的公司。

如果您希望结果包含 northstar 中的所有列，则可以省略此DataFrame的列列表。另一方面，我在您的代码中看到了您包括了列列表（您似乎想省略一些现有的列）。

即使键存在也存在KeyError

！/ usr / bin / env python3

标准库

2 个答案: