CODEWITHSUNDEEP
pythonpandas
Nakeuh
Nakeuh

Reputation: 1919

Pandas join DataFrame and Series over a column

I have a Pandas DataFrame df that store a matching between a label and an integer, and a Pandas Series s that contains a sequence of labels : 

print(df)

          label    id
0     AAAAAAAAA     0
1     BBBBBBBBB     1
2     CCCCCCCCC     2
3     DDDDDDDDD     3
4     EEEEEEEEE     4


print(s)

0        AAAAAAAAA
1        BBBBBBBBB
2        CCCCCCCCC
3        CCCCCCCCC
4        EEEEEEEEE
5        EEEEEEEEE
6        DDDDDDDDD

I want to join this DataFrame and this Series, to get the sequence of integer corresponding to my sequence s. Here is the expected result of my example : 

print(df.join(s)["id"])

0        0
1        1
2        2
3        2
4        4
5        4
6        3

Upvotes: 1

Views: 43

Answers (1)

jezrael
jezrael

Reputation: 863116

Use Series.map with Series:

print (s.map(df.set_index('label')['id']))
0    0
1    1
2    2
3    2
4    4
5    4
6    3
Name: a, dtype: int64

Alternative - be careful, if dupes no error but return last dupe row:

print (s.map(dict(zip(df['label'], df['id']))))

Upvotes: 2

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