How do you convert a column to an array in pandas?

How to replace values in list in column pandas?

I have a dataframe with a column named x.

This column has two values. I want to change those values, lets say first with z and second with a.

I tried to do it like this: import pandas as pd. From datetime import date. Df = pd.readexcel('test.todatetime(i).toexcel('test2.xlsx', index=False)
But I get this error: File "C:UsersjeszAppDataLocalProgramsPythonPython36libsite-packagespandascoreinternals.py", line 3202, in ensureindex raise ValueError('Cannot add index for %r, type already exists' % k). ValueError: Cannot add index for , type already exists
How can I change value in column x? When you try to convert the DataFrame to a datetime index, then Pandas tries to add a datetime index for that DataFrame. But this means that the index would contain datetimes, and not integers. In your case you have an integer index, but a list of datetimes. So when you try to add a datetime index, Pandas throws an error.

If you remove the indexing of the column x, Pandas will just convert the column to a datetime index.

How to replace the values of a column in pandas?

I have a data frame with values that I want to replace with the last one of the same name.

Example: col1 col2 col3. A 1 2. B 3 4. I would like to replace the values of col3 with the last value of the same name. This should give the desired result: My solution is: df = df.replace(df.groupby('col3').last(), axis=1)
The result is: Is there a better way to do this?groupby('col3').transform('last') print (df). col1 col2 col3. 0 A 1 2. 1 B 3 4. Another solution is add groupby and apply last: df = df.groupby('col3').apply(lambda x: x.