is_leap_year: Is 'x' a leap year?

In datey: Exact Date and Duration Arithmetic on an Annual Grid

Is x a leap year?

Description

Tests whether a date or year is a leap year.

This returns NA if the corresponding datey would be invalid, including years before 1000 and dates after 3000-01-01.0.

For numerics, this returns NA for years values less than 1000 or greater than 3000.

This is an S3 generic. This package provides methods for:

• numeric types double and integer (interpreted as calendar years, e.g. 2000.9 means the calendar year 2000), and

• date types datey, Date, POSIXct and POSIXlt.

Usage

is_leap_year(x)

## Default S3 method:
is_leap_year(x)

## S3 method for class 'integer'
is_leap_year(x)

## S3 method for class 'double'
is_leap_year(x)

## S3 method for class 'datey'
is_leap_year(x)

## S3 method for class 'Date'
is_leap_year(x)

## S3 method for class 'POSIXct'
is_leap_year(x)

## S3 method for class 'POSIXlt'
is_leap_year(x)

Arguments

x	A vector date type or numeric year.

Value

NA if x is not interpretable as a year or date, or outside [1000,3000], TRUE if x is a leap year, otherwise FALSE.

See Also

datey

Examples

any(is_leap_year(c(1900, 1901, 2001))) #FALSE
all(is_leap_year(c(1904.1, 2000.5, 2004.9))) #TRUE

datey documentation built on July 14, 2026, 5:06 p.m.