hist.POSIXt {graphics} | R Documentation

## Histogram of a Date or Date-Time Object

### Description

Method for `hist` applied to date or date-time objects.

### Usage

    ## S3 method for class 'POSIXt'
    hist(x, breaks, ...,
         xlab = deparse(substitute(x)),
         plot = TRUE, freq = FALSE,
         start.on.monday = TRUE, format)

    ## S3 method for class 'Date'
    hist(x, breaks, ...,
         xlab = deparse(substitute(x)),
         plot = TRUE, freq = FALSE,
         start.on.monday = TRUE, format)

### Arguments

`x` | an object inheriting from class `"POSIXt"` or `"Date"`.
`breaks` | a vector of cut points or number giving the number of intervals which `x` is to be cut into or an interval specification, one of `"days"`, `"weeks"`, `"months"`, `"quarters"` or `"years"`, plus `"secs"`, `"mins"`, `"hours"` for date-time objects.
`...` | graphical parameters, or arguments to `hist.default` such as `include.lowest`, `right` and `labels`.
`xlab` | a character string giving the label for the x axis, if plotted.
`plot` | logical. If `TRUE` (default), a histogram is plotted, otherwise a list of breaks and counts is returned.
`freq` | logical; if `TRUE`, the histogram graphic is a representation of frequencies, i.e, the `counts` component of the result; if `FALSE`, relative frequencies (probabilities) are plotted.
`start.on.monday` | logical. If `breaks = "weeks"`, should the week start on Mondays or Sundays?
`format` | for the x-axis labels. See `strptime`.

### Details

Note that unlike the default method, `breaks` is a required argument.

Using `breaks = "quarters"` will create intervals of 3 calendar months, with the intervals beginning on January 1, April 1, July 1 or October 1, based upon `min(x)` as appropriate.

### Value

An object of class `"histogram"`: see `hist`.

### See Also

`seq.POSIXt`, `axis.POSIXct`, `hist`

### Examples

    hist(.leap.seconds, "years", freq = TRUE)
    hist(.leap.seconds,
         seq(ISOdate(1970, 1, 1), ISOdate(2010, 1, 1), "5 years"))

    ## 100 random dates in a 10-week period
    random.dates <- as.Date("2001/1/1") + 70*stats::runif(100)
    hist(random.dates, "weeks", format = "%d %b")

[Package graphics version 2.15.1 Index]