Subsetting data.tables
Returns subsets of a data.table.
## S3 method for class 'data.table' subset(x, subset, select, ...)
x |
|
subset |
logical expression indicating elements or rows to keep |
select |
expression indicating columns to select from |
... |
further arguments to be passed to or from other methods |
The subset argument works on the rows and will be evaluated
in the data.table so columns can be referred to (by name) as variables
in the expression.
The data.table that is returned will maintain the original keys
as long as they are not select-ed out.
A data.table containing the subset of rows and columns that are
selected.
DT <- data.table(a=sample(c('a', 'b', 'c'), 20, replace=TRUE),
b=sample(c('a', 'b', 'c'), 20, replace=TRUE),
c=sample(20), key=c('a', 'b'))
sub <- subset(DT, a == 'a')
all.equal(key(sub), key(DT))Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.