rollmean {zoo} | R Documentation |

## Rolling Means/Maximums/Medians

### Description

Generic functions for computing rolling means, maximums and medians of ordered observations.

### Usage

rollmean(x, k, na.pad = FALSE, align = c("center", "left", "right"), ...)
rollmax(x, k, na.pad = FALSE, align = c("center", "left", "right"), ...)
rollmedian(x, k, na.pad = FALSE, align = c("center", "left", "right"), ...)

### Arguments

`x` |
an object (representing a series of observations). |

`k` |
integer width of the rolling window. Must be odd for `rollmedian` . |

`na.pad` |
logical. Should `NA` padding be added at beginning? |

`align` |
character specifying whether result should be left- or
right-aligned or centered (default). |

`...` |
Further arguments passed to methods. |

### Details

These functions compute rolling means, maximums and medians respectively
and are thus similar to `rapply`

but are
optimized for speed.

Currently, there are methods for `"zoo"`

and `"ts"`

series and
default methods (intended for vectors). The default method of `rollmedian`

is an interface to `runmed`

.
The default method of `rollmean`

does not handle inputs that contain
`NA`

s. In such cases, use `rapply`

instead.

### Value

An object of the same class as `x`

with the rolling mean/max/median.

### See Also

`rapply`

, `zoo`

### Examples

x.Date <- as.Date(paste(2004, rep(1:4, 4:1), sample(1:28, 10), sep = "-"))
x <- zoo(rnorm(12), x.Date)
rollmean(x, 3)
rollmax(x, 3)
rollmedian(x, 3)
xm <- zoo(matrix(1:12, 4, 3), x.Date[1:4])
rollmean(xm, 3)
rollmax(xm, 3)
rollmedian(xm, 3)
rapply(xm, 3, mean) # uses rollmean
rapply(xm, 3, function(x) mean(x)) # does not use rollmean

[Package

*zoo* version 1.0-5

Index]