CODEWITHSUNDEEP
pythonpandas
Michael
Michael

Reputation: 371

Pandas multi index loc

I have a pandas dataframe for graph edges with a multi index as such

df = pd.DataFrame(index=[(1, 2), (2, 3), (3, 4), ...], data=['v1', 'v2', 'v3', ...])

However doing a simple .loc fails:

df.loc[(1, 2)]       # error
df.loc[df.index[0]]  # also error

with the message KeyError: 1. Why does it fail? The index clearly shows that the tuple (1, 2) is in it and in the docs I see .loc[] being used similarly.

Edit: Apparently df.loc[[(1, 2)]] works. Go figure. It was probably interpreting the first iterable as separate keys?

Upvotes: 1

Views: 1546

Answers (1)

Michael
Michael

Reputation: 371

Turns out I needed to wrap the key in another iterable like a list for it to use the whole tuple instead of its elements like so: df.loc[[(1, 2)]].

Upvotes: 2

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