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Last data update: 2014.03.03

R: Extract/Replacing the Time Windows of Objects

window.zoo

R Documentation

Extract/Replacing the Time Windows of Objects

Description

Methods for extracting time windows of "zoo" objects and replacing it.

Usage

## S3 method for class 'zoo'
window(x, index. = index(x), start = NULL, end = NULL, ...)
## S3 replacement method for class 'zoo'
window(x, index. = index(x), start = NULL, end = NULL, ...) <- value

Arguments

`x`	an object.
`index.`	the index/time window which should be extracted.
`start`	an index/time value. Only the indexes in `index` which are greater or equal to `start` are used. If the index class supports comparisons to character variables, as does `"Date"` class, `"yearmon"` class, `"yearqtr"` class and the `chron` package classes `"dates"` and `"times"` then `start` may alternately be a character variable.
`end`	an index/time value. Only the indexes in `index` which are lower or equal to `end` are used. Similar comments about character variables mentioned under `start` apply here too.
`value`	a suitable value object for use with `window(x)`.
`...`	currently not used.

Value

Either the time window of the object is extracted (and hence return a "zoo" object) or it is replaced.

Examples

## zoo example
x.date <- as.Date(paste(2003, rep(1:4, 4:1), seq(1,19,2), sep = "-"))
x <- zoo(matrix(rnorm(20), ncol = 2), x.date)
x

window(x, start = as.Date("2003-02-01"), end = as.Date("2003-03-01"))
window(x, index = x.date[1:6], start = as.Date("2003-02-01"))
window(x, index = x.date[c(4, 8, 10)])
window(x, index = x.date[c(4, 8, 10)]) <- matrix(1:6, ncol = 2)
x

## for classes that support comparisons with "character" variables
## start and end may be "character".
window(x, start = "2003-02-01")

## zooreg example (with plain numeric index)
z <- zooreg(rnorm(10), start = 2000, freq = 4)
window(z, start = 2001.75)
window(z, start = c(2001, 4))

## replace data at times of d0 which are in dn
d1 <- d0 <- zoo(1:10) + 100
dn <- - head(d0, 4)

window(d1, time(dn)) <- coredata(dn)