🔒 AttributeError when trying to rename column header on Pandas dataframe

[deft panther]

Trying to rename the column header on a dataframe before I write it to an excel sheet. The dataframe only has one column and I get this error when writing. The df will write just fine if I don't try to rename it.

AttributeError: 'NoneType' object has no attribute 'to_excel'

df2 = df2.rename(columns={'service_groups': 'Service Groups'}, inplace=True)
df2.to_excel(writer, sheet_name="Summary", startrow=0, startcol=start_column, index=False)```

[verbal storm]

@deft panther

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[cinder canopy]

df2 = df2.rename(columns={'service_groups': 'Service Groups'}, inline=True)
``` I assume `inline` is actually `inplace` in which case the function doesn't return anything

[deft panther]

yes. Inplace

I changed that after I copied my code to the clipboard

[cinder canopy]

inplace means change the current object, do not return anything so df2 was replaced with None

[proper scaffold]

It's one of weird things pandas does, you can optimise the stuff by doing stuff in place, but then the method returns None instead of the result (so it behaves like any in-place thing usually behaves)

[cinder canopy]

you could either remove df2 = or inplace = True and it should work

[deft panther]

I removed inplace=True and df2 = and it doesn't rename. Still service_groups.

new code

df2.rename(columns={"service_groups": "Service Groups"})
df2.to_excel(writer, sheet_name="Summary", startrow=0, startcol=start_column, index=False)```

[broken pine]

Either, not both. ```py
df2 = df2.rename(columns={'service_groups': 'Service Groups'})

or

df2.rename(columns={'service_groups': 'Service Groups'}, inplace=True)```

[cinder canopy]

one or the other, not both

[deft panther]

I did it both ways as @broken pine mentioned and neither work to change the header.

[cinder canopy]

print(df2.columns) and copy-paste the exact output you get

[deft panther]

Index(['service_group'], dtype='object')

[cinder canopy]

service_group not service_groups, you are trying to rename nonexisting column

[deft panther]

🤦‍♂️

I'm a moron.

[raven pewter]

If you use inplace=True, the DataFrame is changed in place, meaning the method returns nothing, but the object is modified. In that case only, do not assign its output (you'll get df2 == None)

If you do not use inplace arg, the method will return a changed DataFrame object, and that must be assigned in order to "save" that change.

Using inplace is generally discouraged due to this confusion. Most of the time, just use assignment, or chain methods together.

[cinder canopy]

simple mistake to make, best to just copy-paste the actual column names that you can print out, lets you be sure you're not making a typo

[deft panther]

Thanks all.

!close

!close

[verbal storm]

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