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.

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.

Details

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