Kevin Sun Kevin Sun - 26 days ago 19
Python Question

how to rename columns in pandas using a list

I have a dataframe (df) that has 44 columns and I want to rename columns 2:44. I have a list (namesList) of length 42 that has the new column names. I then try to rename my columns by using the list:

df.columns[2:len(df.columns)] = namesList


However I get the error:


TypeError: Index does not support mutable operations


Why do I get this error?

Answer

You need generate new columns names - first and second value from old one and another from list:

df.columns = df.columns[:2].tolist() + namesList

Sample:

df = pd.DataFrame({'A':[1,2,3],
                   'B':[4,5,6],
                   'C':[7,8,9],
                   'D':[1,3,5],
                   'E':[5,3,6],
                   'F':[7,4,3]})

print (df)
  A  B  C  D  E  F
0  1  4  7  1  5  7
1  2  5  8  3  3  4
2  3  6  9  5  6  3

namesList = ['K','L','M','N']
df.columns = df.columns[:2].tolist() + namesList
print (df)
   A  B  K  L  M  N
0  1  4  7  1  5  7
1  2  5  8  3  3  4
2  3  6  9  5  6  3
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