Hmisc (version 4.1-0)

Lag: Lag a Numeric, Character, or Factor Vector

Description

Shifts a vector shift elements later. Character or factor variables are padded with "", numerics with NA. The shift may be negative.

Usage

Lag(x, shift = 1)

Arguments

x

a vector

shift

integer specifying the number of observations to be shifted to the right. Negative values imply shifts to the left.

Value

a vector like x

Details

A.ttributes of the original object are carried along to the new lagged one.

See Also

lag

Examples

# NOT RUN {
Lag(1:5,2)
Lag(letters[1:4],2)
Lag(factor(letters[1:4]),-2)
# Find which observations are the first for a given subject
id <- c('a','a','b','b','b','c')
id != Lag(id)
!duplicated(id)
# }