lead-lag

0th

Percentile

Lead and lag.

Find the "next" or "previous" values in a vector. Useful for comparing values ahead of or behind the current values.

Usage
lead(x, n = 1L, default = NA, order_by = NULL, ...)

lag(x, n = 1L, default = NA, order_by = NULL, ...)

Arguments
x

a vector of values

n

a positive integer of length 1, giving the number of positions to lead or lag by

default

value used for non-existent rows. Defaults to NA.

order_by

override the default ordering to use another vector

...

Needed for compatibility with lag generic.

Aliases
  • lead-lag
  • lead
  • lag
Examples
# NOT RUN {
lead(1:10, 1)
lead(1:10, 2)

lag(1:10, 1)
lead(1:10, 1)

x <- runif(5)
cbind(ahead = lead(x), x, behind = lag(x))

# Use order_by if data not already ordered
df <- data.frame(year = 2000:2005, value = (0:5) ^ 2)
scrambled <- df[sample(nrow(df)), ]

wrong <- mutate(scrambled, prev = lag(value))
arrange(wrong, year)

right <- mutate(scrambled, prev = lag(value, order_by = year))
arrange(right, year)
# }
Documentation reproduced from package dplyr, version 0.7.8, License: MIT + file LICENSE

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