Reorder few columns only out of hundreds

Question

What is the most efficient way to reorder columns for data frames with hundreds even thousands of columns?

The following is tried and it works, however I am looking for an optimal function.

dput(names(df1)) to dump all column names and used in the following step

swapped columns with df1[c(col1, col3, col2,.....col99,col100)

ex names(df1)
"col1" "col2" "col3".............."col99" "col100"

Want to swap only "col2" and "col3", with

names(df1)
"col1" "col3" "col2".............."col99" "col100"

Answer 1

df1 = df1[,c(1,3,2,4:100)]

reorders your columns according to the permutation c(1,3,2,4:100)