Operators for datey, durationy and datey_interval

The unary - operator can be applied to a durationy to change its sign.

The following are the available binary operations on datey and durationy only operands, and their meaning:

Left	Operators	Right	Result	Notes
`datey`	`==` `!=` `<` `<=` `>` `>=`	`datey`	logical	Order relation for dates
`datey`	`-`	`datey`	`durationy`	Duration between two dates
`datey`	`+` `-`	`durationy`	`datey`	A date offset by a duration
`durationy`	`+`	`datey`	`datey`	A date offset by a duration
`durationy`	`==` `!=` `<` `<=` `>` `>=`	`durationy`	logical	Order relation for durations
`durationy`	`+` `-`	`durationy`	`durationy`	Duration addition and substraction
`datey`	`+` `-` `==` `!=` `<` `<=` `>` `>=`	numeric	numeric	The `datey` is first converted to years
numeric	`+` `-` `==` `!=` `<` `<=` `>` `>=`	`datey`	numeric	The `datey` is first converted to years
`durationy`	`+` `-` `*` `/` `==` `!=` `<` `<=` `>` `>=`	numeric	`durationy`	The `durationy` is first converted to years
numeric	`+` `-` `*` `/` `==` `!=` `<` `<=` `>` `>=`	`durationy`	`durationy`	The `durationy` is first converted to years
`datey`	`%to%`	`datey`	`datey_interval`	Syntactic sugar for `datey_interval()`
`datey_interval`	`%includes%`	`datey`	logical	Whether the interval contains the date

Usage

# S3 method for class 'datey_type'
Ops(e1, e2)

Arguments

e1: First parameter.
e2: Second parameter (missing if a unary operator).

Value

See above table. In essence

subtracting two dateys results in a durationy,
comparing two Ts results in a logical,
adding or subtracting a durationy to or from a T results in a T, and
mixing durationy and datey with numeric operands first converts the durationy and datey to years and then results in standard numeric evaluation,

where T is either datey or durationy in each of the above.

Examples

t_2000 <- datey(2000)
t_2001 <- datey(2001)
d_0.5 <- durationy(0.5)

t_2000
#> [1] 2000-01-01.0
t_2001
#> [1] 2001-01-01.0
d_0.5
#> [1] 0.5 yr

t_2001 - t_2000 # `datey` - `datey` is a `durationy`
#> [1] 1 yr
t_2000 + d_0.5  # `datey` + `durationy` is a `datey`
#> [1] 2000-07-02.0
t_2001 - d_0.5  # `datey` - `durationy` is a `datey`
#> [1] 2000-07-02.0
t_2000 + 0.5    # Arithmetic with numerics results in a double
#> [1] 2000.5
d_0.5 + d_0.5   # `durationy` + `durationy` is a `durationy`
#> [1] 1 yr
d_0.5 + 0.5     # Arithmetic with numerics results in a double
#> [1] 1
d_0.5 * 2       # Arithmetic with numerics results in a double
#> [1] 1

interval <- t_2000 %to% t_2001
interval
#> [1] [2000-01-01.0, 2001-01-01.0)
interval %includes% t_2000 # TRUE -- start *is* included in an interval
#> [1] TRUE
interval %includes% (t_2000 + d_0.5) # TRUE
#> [1] TRUE
interval %includes% t_2001 # FALSE -- end is *not* included in an interval
#> [1] FALSE