Lag: Lag a Numeric, Character, or Factor Vector

Description Usage Arguments Details Value Author(s) See Also Examples

View source: R/Misc.s

Description

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

Usage

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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.

Details

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

Value

a vector like x

Author(s)

Frank Harrell

See Also

lag

Examples

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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)

harrelfe/Hmisc documentation built on Oct. 3, 2019, 9:34 p.m.