How to change the name of single column using setNames in R?

To change the name of single column using setNames, we would need to specify the column name that needs to be changed.

For example, if we have a data frame called df that contains three columns say Var1, var2, and Var3 and we want to change var2 to Var2 then we can use the command as follows −

setNames(df,replace(names(df),names(df)=="var2","Var2"))

Example 1

Following snippet creates a sample data frame −

x<-rnorm(20) x1<-rnorm(20) df1<-data.frame(x,x1) df1

Output

The following dataframe is created −

       x            x1 1   0.885142314  -0.18025261 2  -0.048954839   0.87720112 3   0.896212666  -0.53714354 4   0.539095496  -0.19380810 5  -1.706763224   0.79608177 6  -1.628122107  -1.17570164 7  -1.000949495   0.09243436 8   1.344899293  -0.34504828 9   0.290659812   0.57493564 10 -1.366119792   0.39442545 11 -0.002044629  -0.60124159 12  1.056147083  -0.05670359 13  1.245766258  -0.91321178 14  1.202689649   0.42440362 15 -1.238028330  -1.31709063 16  0.962875354   1.43057923 17  0.692604922  -0.60277152 18  1.721352577   0.67629134 19 -2.373829503  -0.09540660 20  0.031280271   1.90790870

In order to change the name of column x1 to y, add the following code to the above snippet −

x<-rnorm(20) x1<-rnorm(20) df1<-data.frame(x,x1) setNames(df1,replace(names(df1),names(df1)=="x1","y"))

Output

If you execute all the above given codes as a single program, it generates the following output −

         x           y 1   0.885142314  -0.18025261 2  -0.048954839   0.87720112 3   0.896212666  -0.53714354 4   0.539095496  -0.19380810 5  -1.706763224   0.79608177 6  -1.628122107  -1.17570164 7  -1.000949495   0.09243436 8   1.344899293  -0.34504828 9   0.290659812   0.57493564 10 -1.366119792   0.39442545 11 -0.002044629  -0.60124159 12  1.056147083  -0.05670359 13  1.245766258  -0.91321178 14  1.202689649   0.42440362 15 -1.238028330  -1.31709063 16  0.962875354   1.43057923 17  0.692604922  -0.60277152 18  1.721352577   0.67629134 19 -2.373829503  -0.09540660 20  0.031280271   1.90790870

Example 2

Following snippet creates a sample data frame −

a<-rpois(20,5) a_2<-rpois(20,2) df2<-data.frame(a,a_2) df2

Output

The following dataframe is created −

   a a_2 1  5  7 2  3  2 3  7  2 4  5  0 5  6  0 6  4  1 7  8  3 8  6  1 9  7  2 10 6  3 11 4  0 12 3  2 13 5  0 14 7  2 15 3  1 16 9  3 17 2  2 18 4  1 19 2  7 20 1  1

In order to change the name of column a_2 to b, add the following code to the above snippet −

a<-rpois(20,5) a_2<-rpois(20,2) df2<-data.frame(a,a_2) df2<-data.frame(a,a_2) setNames(df2,replace(names(df2),names(df2)=="a_2","b"))

Output

If you execute all the above given codes as a single program, it generates the following output −

   a  b 1  5  7 2  3  2 3  7  2 4  5  0 5  6  0 6  4  1 7  8  3 8  6  1 9  7  2 10 6  3 11 4  0 12 3  2 13 5  0 14 7  2 15 3  1 16 9  3 17 2  2 18 4  1 19 2  7 20 1  1