Question

我有两个数据框。第二数据帧是从第一数据帧派生的。我在第二个数据框中更新一列，然后将更新后的值放回第一个数据框中。我已经尝试过“合并”，但是它为我提供了带有后缀“ _x”和“ _y”的两列

import pandas

lotQtyQueryForDF = pandas.read_sql_query(refreshQuery,conForInfo)
dataFrameOfLots = pandas.DataFrame(lotQtyQueryForDF,columns=['Customer','Stage','ProdType','Brand','ProdName','Size','Strength','Lot','PackedOn','Qty','Available'])

dataFrameOfLots['Available']=dataFrameOfLots["Available"].fillna(dataFrameOfLots['Qty'])
#inserting columns
dataFrameOfLots['QtyInTransaction']=0   
dataFrameOfLots['IndexCol'] = range(1, len(dataFrameOfLots) + 1)

dataFrameFiltered=dataFrameOfLots.query('Brand=="XYZ" & Customer=="ABC"')
dataFrameFiltered.loc[:,'Qty in transaction']=34
dataFrameFiltered2=dataFrameFiltered[['Qty in transaction','IndexCol']].copy()
dataFrameOfLots.merge(dataFrameFiltered2,on='IndexCol',how='outer')

输入数据集：

Customer Stage ProdType Brand ProdName Size Strength Lot PackedOn Qty Available

DEF      A       Bulk    YYY   Test    Test   Weak    1   20200101 10    5            

ABC      A       Bulk    XYZ   Test    Test   Weak    1   20200101 10    5            

GHI      A       Bulk    YTY   Test    Test   Weak    1   20200101 10    5            

ABC      B       RAW     XYZ   Test    Test   Weak    1   20200101 10    5

实际输出：

Customer Stage ProdType Brand ProdName Size Strength Lot PackedOn Qty Available QtyInTransaction_x IndexCol QtyInTransaction_y

DEF      A       Bulk    YYY   Test    Test   Weak    1   20200101 10    5            0               1             0 

ABC      A       Bulk    XYZ   Test    Test   Weak    1   20200101 10    5            0               2             34 

GHI      A       Bulk    YTY   Test    Test   Weak    1   20200101 10    5            0               3             0 

ABC      B       RAW     XYZ   Test    Test   Weak    1   20200101 10    5            0               4             34

预期输出：

Customer Stage ProdType Brand ProdName Size Strength Lot PackedOn Qty Available IndexCol QtyInTransaction

DEF      A       Bulk    YYY   Test    Test   Weak    1   20200101 10    5           1             0 

ABC      A       Bulk    XYZ   Test    Test   Weak    1   20200101 10    5           2             34 

GHI      A       Bulk    YTY   Test    Test   Weak    1   20200101 10    5           3             0 

ABC      B       RAW     XYZ   Test    Test   Weak    1   20200101 10    5           4             34

查询方法正确吗？我将如何合并以便只显示一列？

谢谢

Answer 1

在执行过滤器后，请尝试使用外部合并并删除不需要的行。下面的代码。

result=pd.merge(dataFrameOfLots, dataFrameFiltered, how='outer', on=['Customer', 'Stage', 'ProdType', 'Brand', 'ProdName', 'Size',
       'Strength', 'Lot', 'PackedOn', 'Qty', 'Available'],suffixes=('_x', '')).fillna(0)
result=result.loc[:,~result.columns.str.endswith('_x')]#drop unwanted columns

或

result.drop(columns=['QtyInTransaction_x','IndexCol_x'], inplace=True)#drop unwanted columns

如果在另一数据框的列中找到ID匹配，则更新数据框中的一列的值

1 个答案: