| firstlastobs(doBy) | R Documentation |
Locate the index of the first/last unique value
Description
Locate the index of the first/last unique value in i) a vector or of a variable in a data frame.
Usage
## S3 method for class 'formula': firstobs(formula, data=parent.frame(), ...) ## S3 method for class 'formula': lastobs(formula, data=parent.frame(), ...) firstobs(x, ...) lastobs(x, ...)
Arguments
x |
A vector |
formula |
A formula (only the first term is used, see 'details'). |
data |
A data frame |
... |
Currently not used |
Details
If writing ~a+b+c as formula, then only a is considered.
Value
A vector.
Author(s)
Søren Højsgaard, [email protected]
Examples
x <- c(rep(1,5),rep(2,3),rep(3,7),rep(1,4)) firstobs(x) lastobs(x) data(dietox) firstobs(~Pig, data=dietox) lastobs(~Pig, data=dietox)
[Package doBy version 2.2 Index]