| split {base} | R Documentation |
Divide into Groups
Description
split divides the data in the vector x into the groups
defined by the factor f.
Usage
split(x, f)
split.default(x, f)
split.data.frame(x, f)
Arguments
x |
vector containing the values to be divided into groups. |
f |
a “factor” such that |
Details
f is recycled as necessary and
if the length of x is not a multiple of the length of f
a warning is printed.
Value
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.
See Also
cut
Examples
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)