difftime {base} | R Documentation |

Create, print and round time intervals.

time1 - time2 difftime(time1, time2, tz = "", units = c("auto", "secs", "mins", "hours", "days", "weeks")) as.difftime(tim, format = "%X", units="auto") ## S3 method for class 'difftime': round(x, digits = 0, ...) ## S3 method for class 'difftime': format(x, ...) ## S3 method for class 'difftime': units(x) ## S3 method for class 'difftime': units(x) <- value ## S3 method for class 'difftime': as.double(x, units="auto", ...)

`time1, time2` |
date-time or date objects. |

`tz` |
a timezone specification to be used for the conversion.
System-specific, but `""` is the current time zone, and
`"GMT"` is UTC. |

`units` |
character. Units in which the results are desired. Can be abbreviated. |

`value` |
character. Like `units` above, except that
abbreviations are not allowed. |

`tim` |
character string or numeric value specifying a time interval. |

`format` |
character specifying the format of `tim` : see
`strptime` . The default is a locale-specific time format. |

`x` |
an object inheriting from class `"difftime"` . |

`digits` |
integer. Number of significant digits to retain. |

`...` |
arguments to be passed to or from other methods. |

Function `difftime`

calculates a difference of two date/time objects
and returns an object of class `"difftime"`

with an attribute indicating the units. There is a `round`

method for objects of this class, as well as methods for the
group-generic (see `Ops`

) logical and
arithmetic operations.

If `units = "auto"`

, a suitable set of units is chosen, the largest
possible (excluding `"weeks"`

) in which all the absolute
differences are greater than one.

Subtraction of date-time objects gives an object of this class,
by calling `difftime`

with `units="auto"`

. Alternatively,
`as.difftime()`

works on character-coded or numeric time
intervals; in the latter case, units must be specified, and
`format`

has no effect.

Limited arithmetic is available on `"difftime"`

objects: they can
be added or subtracted, and multiplied or divided by a numeric vector.
In addition, adding or subtracting a numeric vector implicitly
converts the numeric vector to a `"difftime"`

object with the
same units as the `"difftime"`

object.

The units of a `"difftime"`

object can be extracted by the
`units`

function, which also has an assignment form. If the units
are changed, the numerical value is scaled accordingly.

The `as.double`

method returns the numeric value expressed in
the specified units. Using `units="auto"`

means the units of the
object.

The `format`

method simply formats the numeric value and appends
the units as a text string.

(z <- Sys.time() - 3600) Sys.time() - z # just over 3600 seconds. ## time interval between releases of 1.2.2 and 1.2.3. ISOdate(2001, 4, 26) - ISOdate(2001, 2, 26) as.difftime(c("0:3:20", "11:23:15")) as.difftime(c("3:20", "23:15", "2:"), format= "%H:%M")# 3rd gives NA (z <- as.difftime(c(0,30,60), units="mins")) as.numeric(z, units="secs") as.numeric(z, units="hours") format(z)

[Package *base* version 2.5.0 Index]