diff {base}

R Documentation

Lagged Differences

Description

Returns suitably lagged and iterated differences.

Usage

diff(x, ...)

## Default S3 method:
diff(x, lag = 1, differences = 1, ...)

## S3 method for class 'POSIXt'
diff(x, lag = 1, differences = 1, ...)

## S3 method for class 'Date'
diff(x, lag = 1, differences = 1, ...)

Arguments

x	a numeric vector or matrix containing the values to be differenced.
lag	an integer indicating which lag to use.
differences	an integer indicating the order of the difference.
...	further arguments to be passed to or from methods.

Details

diff is a generic function with a default method and ones for classes "ts", "POSIXt" and "Date".

NA's propagate.

Value

If x is a vector of length n and differences = 1, then the computed result is equal to the successive differences x[(1+lag):n] - x[1:(n-lag)].

If difference is larger than one this algorithm is applied recursively to x. Note that the returned value is a vector which is shorter than x.

If x is a matrix then the difference operations are carried out on each column separately.

References

Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.

See Also

diff.ts, diffinv.

Examples

diff(1:10, 2)
diff(1:10, 2, 2)
x <- cumsum(cumsum(1:10))
diff(x, lag = 2)
diff(x, differences = 2)

diff(.leap.seconds)
## allows to pass units via ... to difftime()
diff(.leap.seconds, units = "weeks") 
diff(as.Date(.leap.seconds), units = "weeks")

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