poorman (version 0.2.3)

mutate: Create or transform variables

Description

mutate() adds new variables and preserves existing ones; transmute() adds new variables and drops existing ones. Both functions preserve the number of rows of the input. New variables overwrite existing variables of the same name.

Usage

mutate(.data, ...)
transmute(.data, ...)

Arguments

.data

A data.frame.

...

Name-value pairs of expressions, each with length 1L. The name of each argument will be the name of a new column and the value will be its corresponding value. Use a NULL value in mutate to drop a variable. New variables overwrite existing variables of the same name.

Examples

# NOT RUN {
mutate(mtcars, mpg2 = mpg * 2)
mtcars %>% mutate(mpg2 = mpg * 2)
mtcars %>% mutate(mpg2 = mpg * 2, cyl2 = cyl * 2)

# Newly created variables are available immediately
mtcars %>% mutate(mpg2 = mpg * 2, mpg4 = mpg2 * 2)

# You can also use mutate() to remove variables and modify existing variables
mtcars %>% mutate(
  mpg = NULL,
  disp = disp * 0.0163871 # convert to litres
)

# mutate() vs transmute --------------------------
# mutate() keeps all existing variables
mtcars %>%
  mutate(displ_l = disp / 61.0237)

# transmute keeps only the variables you create
mtcars %>%
  transmute(displ_l = disp / 61.0237)

# }