如何将两个不同列中的唯一值复制到第三列

Question

i am trying to copy unique values from two differnt columns.

Answer 1

Your question is confusing. But if you want to check if col A == Col B AND col C == col D and then copy the value to a colD, here is what you can do:

df
FirstName   SecondName  ID1 ID2
    ABC     ABC         2   2
    DFH     GGG         2   2
    HGG     UUU         2   2
    NNN     NNN         3   3

Here is a list comprehension to store the logic and capture the values. If not equal, it will generate a NaN value, that you could change to 0 or '-' or whatever...

id3 = [df.ID1[i] if (df.FirstName[i] == df.SecondName[i]) and (df.ID1[i] == df.ID2[i]) else 'NaN' for i in range(df.shape[0])]

Create the new column:

df['ID3'] = id3

Print the resulting df. It only copies the number when FirstName = SecondName AND ID1 = ID2

    FirstName   SecondName  ID1 ID2 ID3
    ABC          ABC        2   2   2
    DFH          GGG        2   2   NaN
    HGG          UUU        2   2   NaN
    NNN          NNN        3   3   3