我有两个要合并的数据框:
target:
version city_id code
id
4 2 4 5736201000175
26 2 3 8290265000183
27 3 3 9529184000156
30 3 3 9263064000150
34 2 3 9312770000144
54 1 3 8407830000140
55 1 3 5590100000139
city:
federation_unit_id name
id
3 8 SAO PAULO
4 8 CAMPINAS
7 8 BARUERI
8 8 BEBEDOURO
9 8 SANTOS
我想合并它们，将 target 的“city_id”与 city 的“id”合并，最终数据框如下所示:
target:
version city_id code federation_unit_id name
id
4 2 4 5736201000175 8 CAMPINAS
26 2 3 8290265000183 8 SAO PAULO
27 3 3 9529184000156 8 SAO PAULO
30 3 3 9263064000150 8 SAO PAULO
34 2 3 9312770000144 8 SAO PAULO
54 1 3 8407830000140 8 SAO PAULO
55 1 3 5590100000139 8 SAO PAULO
为此，我尝试使用以下代码:
target=target.merge(city, left_on='city_id', right_on='id')
但是它一直让我收到以下 KeyError:
Traceback (most recent call last):
File "/file.py", line 12, in <module>
target=target.merge(city, left_on='index', right_on='city_id')
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/pandas/core/frame.py", line 4437, in merge
copy=copy, indicator=indicator)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/pandas/tools/merge.py", line 38, in merge
copy=copy, indicator=indicator)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/pandas/tools/merge.py", line 210, in __init__
self.join_names) = self._get_merge_keys()
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/pandas/tools/merge.py", line 434, in _get_merge_keys
right_keys.append(right[rk]._values)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/pandas/core/frame.py", line 1997, in __getitem__
return self._getitem_column(key)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/pandas/core/frame.py", line 2004, in _getitem_column
return self._get_item_cache(key)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/pandas/core/generic.py", line 1350, in _get_item_cache
values = self._data.get(item)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/pandas/core/internals.py", line 3290, in get
loc = self.items.get_loc(item)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/pandas/indexes/base.py", 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: 'id'
我不知道我做错了什么:/ 有人可以帮忙吗？
请您参考如下方法:
您可以使用 join
target.join(city, on='city_id')
join 本质上是面向索引的。但是，您可以指定一个替代列以加入构成左侧的数据框中。如果我们在 target 上调用 join 方法，那么我们希望将 'city_id' 指定为该替代列。 city 数据框已经有了合适的索引。
