CODEWITHSUNDEEP
pythonpandasindexing
Nikko
Nikko

Reputation: 1572

Set two columns as tuple index in Pandas

Suppose I have a pandas dataframe with columns 0, 1 and 'Future Connections'. How do I set columns 0 and 1 as one tuple index:

For example this data frame:

0   1        Future Connection
6   840      0.0
4   197      1.0
620 979      0.0

would result to:

0           Future Connection
(6, 840)    0.0
(4, 197)    1.0
(620, 979)  0.0

Upvotes: 3

Views: 4099

Answers (2)

jpp
jpp

Reputation: 164693

How do I set columns 0 and 1 as one tuple index:

"Tuple index" as a concept does not exist in Pandas. You can have an object dtype index containing tuples, but this isn't recommended. The best option is to use a MultiIndex, which stores underlying values efficiently via NumPy arrays. Indeed, Pandas facilitates this with set_index:

df = df.set_index([0, 1])

print(df)
#          Future Connection
# 0   1                     
# 6   840                0.0
# 4   197                1.0
# 620 979                0.0

print(df.index)
# MultiIndex(levels=[[4, 6, 620], [197, 840, 979]],
#            labels=[[1, 0, 2], [1, 0, 2]],
#            names=[0, 1])

print(df.index.values)
# [(6, 840) (4, 197) (620, 979)]

Upvotes: 5

jezrael
jezrael

Reputation: 862771

Use list comprehension with DataFrame.pop for extract column 0, 1:

print (df.columns)
Index([0, 1, 'Future Connection'], dtype='object')

df.index = [x for x in zip(df.pop(0), df.pop(1))]
print (df)
            Future Connection
(6, 840)                  0.0
(4, 197)                  1.0
(620, 979)                0.0

Upvotes: 4

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