Add new Variables to a Data Frame using Existing Variables in R Programming – mutate() Function

mutate() function in R Language is used to add new variables in a data frame which are formed by performing operation on existing variables.

Syntax: mutate(x, expr)

Parameters:
x: Data Frame
expr: operation on variables

Example 1:

# R program to add new variables
# in a data frame

# Loading library
library(dplyr)

# Create a data frame
d <- data.frame( name = c("Abhi", "Bhavesh", "Chaman", "Dimri"),
                 age = c(7, 5, 9, 16),
                 ht = c(46, NA, NA, 69),
                 school = c("yes", "yes", "no", "no") )

# Calculating a variable x3 which is sum of height
# and age printing with ht and age
mutate(d, x3 = ht + age)

Output:

     name age ht school x3
1    Abhi   7 46    yes 53
2 Bhavesh   5 NA    yes NA
3  Chaman   9 NA     no NA
4   Dimri  16 69     no 85

Example 2:

# R program to add new variables
# in a data frame

# Loading library
library(dplyr)

# Create a data frame
d <- data.frame( name = c("Abhi", "Bhavesh", "Chaman", "Dimri"),
                 age = c(7, 5, 9, 16),
                 ht = c(46, NA, NA, 69),
                 school = c("yes", "yes", "no", "no") )

# Calculating a variable x3 which is product of height
# and age printing with ht and age
mutate(d, x3 = ht * age)

Output:

     name age ht school   x3
1    Abhi   7 46    yes  322
2 Bhavesh   5 NA    yes   NA
3  Chaman   9 NA     no   NA
4   Dimri  16 69     no 1104