How would I go about renaming the index on a dask dataframe? I tried it like so
df.index.name = 'foo'
but rechecking df.index.name shows it still being whatever it was previously.
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2 Answers
This does not seem like an efficient way to do it, so I wouldn't be surprised if there is something more direct.
d.index.name starts off as 'foo';
def f(df, name):
df.index.name = name
return df
d.map_partitions(f, 'pow')
The output now has index name of 'pow'. If this is done with the threaded scheduler, I think you also change the index name of d in-place (in which case you don't really need the output of map_partitions).
3 Comments
paulochf
Adding: this strategy can also be applied to rename a Dask Series, just by removing the
.index from f function.
stav
This seems off to me. This generates dask delayed tasks for something that should obviously be immediate. github.com/dask/dask/issues/4950
mdurant
In dask-world, when to use
compute() is up to the user. It may be best to combine with other operations.A bit late, but the following functions:
import dask.dataframe as dd
import pandas as pd
df = pd.DataFrame().assign(s=[1, 2], o=[3, 4], p=[5, 6]).set_index("si")
ddf = dd.from_pandas(df, npartitions=2)
ddf.index = ddf.index.rename("si2")
I hope this can help someone else out!
1 Comment
Thrastylon
Just like for the OP, this didn't actually change the name of the index when I tried it.