| with {base} | R Documentation |
Evaluate an R expression in an environment constructed from data.
with(data, expr, ...)
data |
data to use for constructing an environment. For the
default method this may be an environment, a list, a data frame,
or an integer as in sys.call. |
expr |
expression to evaluate. |
... |
arguments to be passed to future methods. |
with is a generic function that evaluates expr in a
local environment constructed from data. The environment has
the caller's environment as its parent. This is useful for
simplifying calls to modeling functions.
Note that assignments within expr take place in the constructed
environment and not in the user's workspace.
require(stats); require(graphics)
#examples from glm:
## Not run:
library(MASS)
with(anorexia, {
anorex.1 <- glm(Postwt ~ Prewt + Treat + offset(Prewt),
family = gaussian)
summary(anorex.1)
})
## End(Not run)
with(data.frame(u = c(5,10,15,20,30,40,60,80,100),
lot1 = c(118,58,42,35,27,25,21,19,18),
lot2 = c(69,35,26,21,18,16,13,12,12)),
list(summary(glm(lot1 ~ log(u), family = Gamma)),
summary(glm(lot2 ~ log(u), family = Gamma))))
# example from boxplot:
with(ToothGrowth, {
boxplot(len ~ dose, boxwex = 0.25, at = 1:3 - 0.2,
subset = (supp == "VC"), col = "yellow",
main = "Guinea Pigs' Tooth Growth",
xlab = "Vitamin C dose mg",
ylab = "tooth length", ylim = c(0,35))
boxplot(len ~ dose, add = TRUE, boxwex = 0.25, at = 1:3 + 0.2,
subset = supp == "OJ", col = "orange")
legend(2, 9, c("Ascorbic acid", "Orange juice"),
fill = c("yellow", "orange"))
})
# alternate form that avoids subset argument:
with(subset(ToothGrowth, supp == "VC"),
boxplot(len ~ dose, boxwex = 0.25, at = 1:3 - 0.2,
col = "yellow", main = "Guinea Pigs' Tooth Growth",
xlab = "Vitamin C dose mg",
ylab = "tooth length", ylim = c(0,35)))
with(subset(ToothGrowth, supp == "OJ"),
boxplot(len ~ dose, add = TRUE, boxwex = 0.25, at = 1:3 + 0.2,
col = "orange"))
legend(2, 9, c("Ascorbic acid", "Orange juice"),
fill = c("yellow", "orange"))