Add a row in a dataframe under conditions

Question

Imagine I have two pandas dataframes with these values:

Df1

id  value

1    45
2    48
3    78

Df2

id  value

1    45
2    49
3    78

We can see that there are two similar values (for id 1 and 3), and one different.

I want the Df1 to become like this:

Any ideas how I can do that?

Thanks a lot !!

You can see that the condition is the value. If the value is different, then we add for the same id a second value. I would say it's a merge but with the condition of a different value — Abilys38, Dec 17 '18 at 11:32

score 2 · Answer 1 · answered Dec 17 '18 at 11:33

2

You need merge

print(df1.merge(df2, how='outer', on=['value','id']))

Output:

    value   id
0   45      1
1   48      2
2   78      3
3   49      2

answered Dec 17 '18 at 11:33

Sociopath

score 1 · Answer 2 · answered Dec 17 '18 at 11:52

1

You can concatenate, sort by id (if necessary), then drop_duplicates:

df = pd.concat([df1, df2]).sort_values('id').drop_duplicates()

print(df)

   id  value
0   1     45
1   2     48
1   2     49
2   3     78

answered Dec 17 '18 at 11:52

jpp

2 Answers2