Add (insert) a column between two columns in a data.frame

Question

I have a data frame that has columns a, b, and c. I\'d like to add a new column d between b and c.

I know I could just add d at the end by using cbind but h

Answer 1

Create an example data.frame and add a column to it.

df = data.frame(a = seq(1, 3), b = seq(4,6), c = seq(7,9))
df['d'] <- seq(10,12)
df

  a b c  d
1 1 4 7 10
2 2 5 8 11
3 3 6 9 12

Rearrange by column index

df[, colnames(df)[c(1:2,4,3)]]

or by column name

df[, c('a', 'b', 'd', 'c')]

The result is

  a b  d c
1 1 4 10 7
2 2 5 11 8
3 3 6 12 9