我有两个数据框
specialsData看起来像这样:
coll_cusip tran_type maturity_max
0 912810SC3 BB 1.80
1 912810SD1 BB 1.76
2 9128284V9 BB 1.08
然后代码是这样的:
myTradeFrame['NewColumn']=pd.merge(myTradeFrame, specialsData, how='left', left_on = ['coll_cusip','tran_type'], right_on=[ 'coll_cusip', 'tran_type'])
这行代码给我一个错误,即使两个数据帧中都存在键列。我想念什么?
the error message i get is :
len(self.mgr_locs)))
ValueError: Wrong number of items passed 55, placement implies 1
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/apps/qtrinst/install/python/anaconda/envs/sx_anaconda/lib/python3.5/site-packages/IPython/core/interactiveshell.py", line 2850, in run_ast_nodes
if self.run_code(code, result):
File "/apps/qtrinst/install/python/anaconda/envs/sx_anaconda/lib/python3.5/site-packages/IPython/core/interactiveshell.py", line 2927, in run_code
self.showtraceback(running_compiled_code=True)
TypeError: showtraceback() got an unexpected keyword argument 'running_compiled_code'
基本上,myTradeFrame中的NewColumn在coll_cusip和tran_type相交处应具有“ maturity_max”列的值
答案 0 :(得分:1)
pd.merge返回分配给单个列的数据帧。 因此,错误。您可以将代码替换为以下
myTradeFrame = pd.merge(myTradeFrame, specialsData, how='left', on=[ 'coll_cusip', 'tran_type'],suffixes=('_left','_right'))
提示:如果左右数据框中的键相同,则仅在on上使用。