# diff.xts

##### Lags and Differences of xts Objects

Methods for computing lags and differences on `xts`

objects. This
matches most of the functionality of zoo methods, with some default
argument changes.

##### Usage

```
# S3 method for xts
lag(x, k = 1, na.pad = TRUE, ...)
```
# S3 method for xts
diff(x, lag = 1, differences = 1, arithmetic = TRUE, log = FALSE, na.pad = TRUE, ...)

##### Arguments

- x
an

`xts`

object- k
period to lag over

- lag
period to difference over

- differences
order of differencing

- arithmetic
should arithmetic or geometric differencing be used

- log
should (geometric) log differences be returned

- na.pad
pad vector back to original size

- …
additional arguments

##### Details

The primary motivation for having methods specific to `xts`

was to make use of faster C-level code within xts. Additionally,
it was decided that `lag`

's default behavior should
match the common time-series interpretation of that operator --- specifically
that a value at time ‘t’ should be the value at time ‘t-1’
for a positive lag. This is different than `lag.zoo`

as well
as `lag.ts`

.

Another notable difference is that `na.pad`

is set to
TRUE by default, to better reflect the transformation visually
and within functions requiring positional matching of data.

Backwards compatability with zoo can be achieved by setting
`options(xts.compat.zoo.lag=TRUE)`

. This will change the
defaults of lag.xts to k=-1 and na.pad=FALSE.

##### Value

An `xts`

object reflected the desired lag and/or differencing.

##### References

##### Examples

`library(xts)`

```
# NOT RUN {
x <- xts(1:10, Sys.Date()+1:10)
lag(x) # currently using xts-style positive k
# }
# NOT RUN {
<!-- %lagts(x) # same as original lag.xts, to allow for lag.xts to revert to R lag consistency -->
# }
# NOT RUN {
lag(x, k=2)
# }
# NOT RUN {
<!-- %lagts(x, k=2) -->
# }
# NOT RUN {
lag(x, k=-1, na.pad=FALSE) # matches lag.zoo(x, k=1)
diff(x)
diff(x, lag=1)
diff(x, diff=2)
diff(diff(x))
# }
```

*Documentation reproduced from package xts, version 0.9-7, License: GPL (>= 2)*