How to add new column to an dataframe (to the front not end)?

Question

How to add a new variable to an existing data frame, but I want to add to the front not end. eg. my dataframe is

b c d
1 2 3
1 2 3
1 2 3

I

Answer 1

cbind inherents order by its argument order.

User your first column(s) as your first argument

cbind(fst_col , df)

  fst_col   df_col1   df_col2
1 0             0.2      -0.1
2 0             0.2      -0.1
3 0             0.2      -0.1
4 0             0.2      -0.1
5 0             0.2      -0.1

cbind(df, last_col)

  df_col1   df_col2  last_col
1 0.2      -0.1             0
2 0.2      -0.1             0
3 0.2      -0.1             0
4 0.2      -0.1             0
5 0.2      -0.1             0