mutate_cond: mutate cond
In bgctw/dplyrUtil: Utilities for using dplyr

Description Usage Arguments Details Author(s) Examples

mutate acting only on the rows satisfying the condition

1 2	mutate_cond(.data, condition, ..., envir = parent.frame(), na.rmCond = FALSE)

`.data`	data.frame to be modified
`condition`	condition for selecting rows to be modified
`...`	further arguments to `mutate`
`envir`	the frame where the condition is evaluated
`na.rmCond`	set to TRUE to set NA values in cond to FALSE. By default an error is thrown

condition is evaluated in .data inside the parent frame. Hence column names can be used. .data refers to the subset group of the data.frame processed.

Thomas Wutzler

if (require(dplyr)) {
  ans <- iris %>%
    mutate_cond(
      Species == "setosa"
      , Petal.Length = 1.0
    )
  ans %>% filter(Species == "setosa") %>% select(Petal.Length) %>% head() # 1.0
  ans %>% filter(Species != "setosa") %>% select(Petal.Length) %>% head() # orig
}