我想添加一个新列 app_vendor_id
并将其设置为带有 currency
的 MultIndex,但收到错误。
我的代码:
currency = np.array(['BTC','ETH','BCH'])
u = np.array([5000,10000,1046])
cl_bal = pd.DataFrame(np.repeat(u, len(created_at)), index=
pd.MultiIndex.from_product([currency, created_at], names=
['currency', 'created_at']), dtype= int)
cl_bal = cl_bal.pivot_table(index='currency', columns= 'created_at')
cl_bal.columns = cl_bal.columns.droplevel(0)
cl_bal['app_vendor_id'] = 3
cl_bal.set_index(['app_vendor_id', 'currency'])
错误:
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/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 162, in pandas._libs.index.IndexEngine.get_loc File "pandas/_libs/hashtable_class_helper.pxi", line 1492, in pandas._libs.hashtable.PyObjectHashTable.get_item File "pandas/_libs/hashtable_class_helper.pxi", line 1500, in pandas._libs.hashtable.PyObjectHashTable.get_item KeyError: 'currency'
在处理上述异常的过程中,又发生了一个异常:
Traceback (most recent call last): File "histo_var.py", line 202, in cl_bal.set_index(['app_vendor_id', 'currency']) File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/pandas/core/frame
line 3909, in set_index level = frame[col]._values File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/pandas/core/frame.py", line 2688, in getitem return self._getitem_column(key) File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/pandas/core/frame.py", line 2695, in _getitem_column return self._get_item_cache(key) File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/pandas/core/generic.py", line 2489, in _get_item_cache values = self._data.get(item) File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/pandas/core/internals.py", line 4115, in get loc = self.items.get_loc(item) File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/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 162, in pandas._libs.index.IndexEngine.get_loc File "pandas/_libs/hashtable_class_helper.pxi", line 1492, in pandas._libs.hashtable.PyObjectHashTable.get_item pandas._libs.hashtable.PyObjectHashTable.get_item KeyError: 'currency'
最佳答案
在DataFrame.set_index
中使用参数append=True
,因为 currency
已经在 index
中:
created_at = [1,2,3,4]
currency = np.array(['BTC','ETH','BCH'])
u = np.array([5000,10000,1046])
cl_bal = pd.DataFrame(np.repeat(u, len(created_at)),
index=pd.MultiIndex.from_product([currency, created_at],
names= ['currency', 'created_at']),
dtype= int)
cl_bal = cl_bal.pivot_table(index='currency', columns= 'created_at')
cl_bal.columns = cl_bal.columns.droplevel(0)
cl_bal['app_vendor_id'] = 3
df = cl_bal.set_index(['app_vendor_id'], append=True)
print (df)
created_at 1 2 3 4
currency app_vendor_id
BCH 3 1046 1046 1046 1046
BTC 3 5000 5000 5000 5000
ETH 3 10000 10000 10000 10000
关于python - 向 Dataframe 添加新列并设置 MultiIndex,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/57159092/