Example 5-76 Mutating Columns

This example uses the MTCARS ore.frame object that is created by using the ore.push function on the mtcars data.frame object.

The mutate function adds the extra column displ_1 with the value derived from that of column disp. Setting the column to NULL removes the column.

MTCARS <- ore.push(mtcars)
head(mutate(MTCARS, displ_l = disp / 61.0237))
head(transmute(MTCARS, displ_l = disp / 61.0237))
head(mutate(MTCARS, cyl = NULL))
head(mutate(MTCARS, cyl = NULL, hp = NULL, displ_l = disp / 61.0237))

Listing for This Example

R> MTCARS <- ore.push(mtcars)
R> head(mutate(MTCARS, displ_l = disp / 61.0237))
   mpg cyl disp  hp drat    wt  qsec vs am gear carb  displ_l
1 21.0   6  160 110 3.90 2.620 16.46  0  1    4    4 2.621932
2 21.0   6  160 110 3.90 2.875 17.02  0  1    4    4 2.621932
3 22.8   4  108  93 3.85 2.320 18.61  1  1    4    1 1.769804
4 21.4   6  258 110 3.08 3.215 19.44  1  0    3    1 4.227866
5 18.7   8  360 175 3.15 3.440 17.02  0  0    3    2 5.899347
6 18.1   6  225 105 2.76 3.460 20.22  1  0    3    1 3.687092
R> head(transmute(MTCARS, displ_l = disp / 61.0237))
   displ_l
1 2.621932
2 2.621932
3 1.769804
4 4.227866
5 5.899347
6 3.687092
R> head(mutate(mtcars, cyl = NULL))
   mpg disp  hp drat    wt  qsec vs am gear carb
1 21.0  160 110 3.90 2.620 16.46  0  1    4    4
2 21.0  160 110 3.90 2.875 17.02  0  1    4    4
3 22.8  108  93 3.85 2.320 18.61  1  1    4    1
4 21.4  258 110 3.08 3.215 19.44  1  0    3    1
5 18.7  360 175 3.15 3.440 17.02  0  0    3    2
6 18.1  225 105 2.76 3.460 20.22  1  0    3    1
R> head(mutate(mtcars, cyl = NULL, hp = NULL, displ_l = disp / 61.0237))
   mpg disp drat    wt  qsec vs am gear carb  displ_l
1 21.0  160 3.90 2.620 16.46  0  1    4    4 2.621932
2 21.0  160 3.90 2.875 17.02  0  1    4    4 2.621932
3 22.8  108 3.85 2.320 18.61  1  1    4    1 1.769804
4 21.4  258 3.08 3.215 19.44  1  0    3    1 4.227866
5 18.7  360 3.15 3.440 17.02  0  0    3    2 5.899347
6 18.1  225 2.76 3.460 20.22  1  0    3    1 3.687092