# calcLagged

##### Replaces the values in a vector with the result of applying an operation to it and a lagged value

Replaces the values in `x`

with the result of applying an
`operation`

to it and the value that is `lag`

positions
either before it or after it in `x`

, depending on whether
`lag`

is positive or negative. For positive `lag`

the first `lag`

values will be `NA`

, while for negative
`lag`

the last `lag`

values will be `NA`

.
When `operation`

is `NULL`

, the values are moved
`lag`

positions down the vector.

##### Usage

`calcLagged(x, operation = NULL, lag = 1)`

##### Arguments

- x
A

`vector`

containing the values on which the calculations are to be made.- operation
A

`character`

giving the operation to be performed on pairs of values in`x`

. If`operation`

is`NULL`

then the values are moved`lag`

positions down the vector.- lag
A

`integer`

specifying, for the second value in the pair to be operated on, the number positions it is ahead of or behind the current value.

##### Value

A `vector`

containing the result of applying `operation`

to
values in `x`

. For positive `lag`

the first `lag`

values will
be `NA`

, while for negative `lag`

the last `lag`

values will be `NA`

.

##### See Also

##### Examples

```
# NOT RUN {
data(exampleData)
longi.dat$Days.diffs <- calcLagged(longi.dat$xDays, operation ="-")
# }
```

*Documentation reproduced from package growthPheno, version 1.0-13, License: GPL (>= 2)*