Python: how to add a column to a pandas dataframe between two columns?

Question

I would like to add a column to a dataframe between two columns in number labeled columns dataframe. In the following dataframe the first column corresponds to the index while the first row to the name of the columns.

df
   0 0 1 2 3 4 5
   1 6 7 4 5 2 1
   2 0 3 1 3 3 4
   3 9 8 4 3 6 2 

I have tmp=[2,3,5] that I want to put between the columns 4 and 5, so

df
   0 0 1 2 3 4 5 6 
   1 6 7 4 5 2 2 1
   2 0 3 1 3 3 3 4
   3 9 8 4 3 6 5 2 

Answer 1

You can use insert:

df.insert(4, 'new_col_name', tmp)

Note: The insert method mutates the original DataFrame and does not return a copy.

If you use df = df.insert(4, 'new_col_name', tmp), df will be None.