我如何在某些附加条件下对数据框执行vlookup等效操作 [英] how do I perform a vlookup equivalent operation on my dataframe with some additional conditions
问题描述
我正在尝试在python上运行查找等效函数,但是尝试合并和加入时我还没有触手可及.
HI I am trying to run lookup equivalent function on python but having tried merge and join I haven't hit the nail yet.
所以我的第一个df是这个
so my first df is this
list = ['Computer', 'AA', 'Monitor', 'BB', 'Printer', 'BB', 'Desk', 'AA', 'Printer', 'DD', 'Desk', 'BB']
list2 = [1500, 232, 300, 2323, 150, 2323, 250, 2323, 23, 34, 45, 56]
df = pd.DataFrame(list,columns=['product'])
df['number'] = list2
这是df的外观
product number
0 Computer 1500
1 AA 232
2 Monitor 300
3 BB 2323
4 Printer 150
5 BB 2323
6 Desk 250
7 AA 2323
8 Printer 23
9 DD 34
10 Desk 45
11 BB 56
这是第二个数据帧
list_n = ['AA','BB','CC','DD']
list_n2 = ['Y','N','N','Y']
df2 = pd.DataFrame(list_n,columns=['product'])
df2['to_add'] = list_n2
这是df2的外观
product to_add
0 AA Y
1 BB N
2 CC N
3 DD Y
现在,如何将列('to_add')添加到第一个数据帧(df),所以它看起来应该像这样.在excel中,它是一个简单的vlookup.我尝试了'merge'和'join'函数,但是它改变了我df的顺序,我不想改变顺序.有什么想法吗?
Now, how do I add a column ('to_add') to the first dataframe (df) so it should look a bit like this. In excel its a simple vlookup. I tried 'merge' and 'join' functions but its altering the sequence of my df and I don't want the sequencing to change. any ideas?
product price to_add
0 Computer 1500
1 AA 232 Y
2 Monitor 300
3 BB 2323 N
4 Printer 150
5 BB 2323 N
6 Desk 250
7 AA 2323 Y
8 Printer 23
9 DD 34 Y
10 Desk 45
11 BB 56 N
推荐答案
pd.merge
确实可以完成工作,可能您没有正确使用它:
pd.merge
indeed will do the job, probably you were not using it correctly:
pd.merge(df, df2, on="product", how="left")
将返回:
product number to_add
0 Computer 1500 NaN
1 AA 232 Y
2 Monitor 300 NaN
3 BB 2323 N
4 Printer 150 NaN
5 BB 2323 N
6 Desk 250 NaN
7 AA 2323 Y
8 Printer 23 NaN
9 DD 34 Y
10 Desk 45 NaN
11 BB 56 N
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