How to reorder the columns in an R data frame?

Reordering of columns can be done by using square brackets.

Example

> df = data.frame(matrix(rnorm(20), nrow=5))
> df
      X1       X2       X3       X4
1 -0.3637644 2.0770246 0.48763128 -0.09019256
2 -3.1758515 2.3173075 0.86846761 0.38396459
3 1.1844641 0.3412267 1.90986295 -1.03493074
4 -0.5953466 1.7211738 -0.90686896 -0.71215313
5 -0.8732530 0.3256303 0.02312328 -0.36993899

Let’s say we want to change the order of columns as X3, X2, X4, and X1 then it can be done as shown below −

> df[,c(3,2,4,1)]       X3       X2       X4          X1 
1  0.48763128 2.0770246 -0.09019256 -0.3637644 
2  0.86846761 2.3173075  0.38396459 -3.1758515 
3  1.90986295 0.3412267 -1.03493074  1.1844641 
4 -0.90686896 1.7211738 -0.71215313 -0.5953466 
5  0.02312328 0.3256303 -0.36993899 -0.8732530