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I would like to replace entire columns of a pandas dataframe with other columns, for example:

enter image description here

and I would like to replace the columns A and B. What I did is the following:

df['A']=dataFrame['opcodes'].values
df['B']=dataFrame['opt'].values

or also

df['A']=dataFrame['opcodes']
df['B']=dataFrame['opt']

but it does not work. In particular I get the following error:

KeyError: 'opcodes'

in both cases. Can anyone help me? Thank's in advance.

[EDIT] The original dataframe is the following:

enter image description here

on which I did the following modification:

dataFrame['opcodes'] = dataFrame['instructions'].apply(lambda x:[i.split()  [0] for i in x])

now I would like to define an other dataframe on which only the 'opt' column and a column with the values 'opcodes' appear.

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  • $\begingroup$ See my edit below for clarification $\endgroup$
    – HFulcher
    Nov 1, 2019 at 14:56

1 Answer 1

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You are getting a KeyError because 'opcodes' doesn't exist in dataFrame. Can you show us the contents of dataFrame not just df?

EDIT:

You don't need to create an empty DataFrame and then apply the data across. Simply do:

df = dataFrame[["opt", "opcodes"]].copy()
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  • $\begingroup$ Thank's for your answer. By doing is it gives me the following error message: KeyError: "['opcodes'] not in index" $\endgroup$
    – J.D.
    Nov 1, 2019 at 15:02
  • $\begingroup$ Something strange is happening with your dataframe where you are creating opcodes. Are you 100% sure that what you are using has the opcodes column within it? @J.D. $\endgroup$
    – HFulcher
    Nov 1, 2019 at 15:03
  • $\begingroup$ I reloaded all the cells in my jupyter notebook and now it is working fine. Thank you vey much. $\endgroup$
    – J.D.
    Nov 1, 2019 at 15:15
  • $\begingroup$ Happy to help :) $\endgroup$
    – HFulcher
    Nov 1, 2019 at 15:17

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