mutate {plyr} | R Documentation |
This function is very similar to transform
but it executes the transformations iteratively so that
later transformations can use the columns created by
earlier transformations. Like transform, unnamed
components are silently dropped.
mutate(.data, ...)
.data |
the data frame to transform |
... |
named parameters giving definitions of new columns. |
Mutate seems to be considerably faster than transform for large data frames.
subset
, summarise
,
arrange
. For another somewhat different
approach to solving the same problem, see
within
.
# Examples from transform mutate(airquality, Ozone = -Ozone) mutate(airquality, new = -Ozone, Temp = (Temp - 32) / 1.8) # Things transform can't do mutate(airquality, Temp = (Temp - 32) / 1.8, OzT = Ozone / Temp) # mutate is rather faster than transform system.time(transform(baseball, avg_ab = ab / g)) system.time(mutate(baseball, avg_ab = ab / g))