| split {base} | R Documentation |
split divides the data in the vector x into the groups
defined by the factor f.
split(x, f) split.default(x, f) split.data.frame(x, f)
x |
vector containing the values to be divided into groups. |
f |
a ``factor'' such that as.factor(f) defines the grouping. |
f is recycled as necessary and
if the length of x is not a multiple of the length of f
a warning is printed.
The value returned is a list of vectors containing the values for the
groups. The components of the list are named by the factor levels of
f. If f is longer than x some of these will be of
zero length.
n <- 10; nn <- 100 g <- factor(round(n * runif(n * nn))) x <- rnorm(n * nn) + sqrt(codes(g)) xg <- split(x, g) boxplot(xg, col = "lavender", notch = TRUE, varwidth = TRUE) sapply(xg, length) sapply(xg, mean) ## Split a matrix into a list by columns ma <- cbind(x = 1:10, y = (-4:5)^2) split(ma, col(ma)) split(1:10, 1:2)