# Mathematical operations with 'timeDate' objects

`methods-mathOps.Rd`

Functions for mathematical and logical operations on `"timeDate"`

objects.

The functions are:

`Ops,timeDate` | Group 'Ops' generic functions for `"timeDate"` objects, |

`+,timeDate` | Performs arithmetic + operation on `"timeDate"` objects, |

`-,timeDate` | Performs arithmetic - operation on `"timeDate"` objects. |

## Arguments

- e1, e2
usually objects of class

`"timeDate"`

, in the case of addition and subtraction`e2`

may be of class`numeric`

.

## Value

`Ops.timeDate`

these are functions for mathematical operations. Group `Ops`

are
generic functions which manage mathematical operations.

`+.timeDate`

`-.timeDate`

The plus operator `"+"`

performs arithmetic "+" operation on

`"timeDate"`

objects, and the minus operator `"-"`

returns a

`difftime`

object if both arguments `e1`

and `e2`

are `"timeDate"`

objects, or returns a `"timeDate"`

object

`e2`

seconds earlier than `e1`

.

## Examples

```
## Create Character Vectors:
dts = c("1989-09-28", "2001-01-15", "2004-08-30", "1990-02-09")
dts
#> [1] "1989-09-28" "2001-01-15" "2004-08-30" "1990-02-09"
tms = c( "23:12:55", "10:34:02", "08:30:00", "11:18:23")
tms
#> [1] "23:12:55" "10:34:02" "08:30:00" "11:18:23"
## "+/-" -
# Add One Day to a Given timeDate Object:
GMT = timeDate(dts, zone = "GMT", FinCenter = "GMT")
GMT
#> GMT
#> [1] [1989-09-28] [2001-01-15] [2004-08-30] [1990-02-09]
ZUR = timeDate(dts, zone = "GMT", FinCenter = "Europe/Zurich")
ZUR
#> Europe/Zurich
#> [1] [1989-09-28 01:00:00] [2001-01-15 01:00:00] [2004-08-30 02:00:00]
#> [4] [1990-02-09 01:00:00]
GMT + 24*3600
#> GMT
#> [1] [1989-09-29] [2001-01-16] [2004-08-31] [1990-02-10]
ZUR[2] - ZUR[1]
#> Time difference of 4127 days
```