how to change the columns of a dataframe in python
new_columns = {"col1": "1st", "col2": "2nd"}
df_new = df.rename(columns=new_columns)
"""
col1 | col2 | col3 1st | 2nd | col3
a | d | g a | d | g
b | e | h => b | e | h
c | f | i c | f | i
"""