How to multiply each value in a column by a constant in R?

To multiply each value in a column by a constant, we can use multiplication sign *.

For example, if we have a data frame called df that contains a column say x. Now, if we want to multiply each value in x with 10 then we can use the below mentioned command −

df$x<-10*(df$x)

Example 1

Following snippet creates a sample data frame −

x<-rpois(20,1) df1<-data.frame(x) df1

Output

The following dataframe is created −

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

To multiply each value in x with 5, add the following code to the above snippet −

x<-rpois(20,1) df1<-data.frame(x) df1$x<-5*(df1$x) df1

Output

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

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

Example 2

Following snippet creates a sample data frame −

y<-round(rnorm(20),1) df2<-data.frame(y) df2

Output

The following dataframe is created −

     y 1   1.0 2  -1.8 3   0.0 4   0.2 5  -2.9 6   1.0 7  -0.6 8  -1.3 9  -0.2 10 -0.3 11  0.3 12  0.8 13 -0.9 14  0.4 15 -2.2 16  1.1 17  0.5 18  3.0 19  1.6 20  1.0

To multiply each value in y with 2, add the following code to the above snippet −

y<-round(rnorm(20),1) df2<-data.frame(y) df2$y<-2*(df2$y) df2

Output

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

     y 1   2.0 2  -3.6 3   0.0 4   0.4 5  -5.8 6   2.0 7  -1.2 8  -2.6 9  -0.4 10 -0.6 11  0.6 12  1.6 13 -1.8 14  0.8 15 -4.4 16  2.2 17  1.0 18  6.0 19  3.2 20  2.0