Reference · Dates

date.is_leap_year

date.is_leap_year(int | str) -> bool

What it does

Whether a year has a 29th of February: true for years divisible by 4, except centuries, except those divisible by 400 (the Gregorian rule). It takes the year as an int, or a date or date-time, whose year it uses.

Examples

print(date.is_leap_year(2024), date.is_leap_year(2023))print(date.is_leap_year(1900), date.is_leap_year(2000))print(date.is_leap_year("2024-06-01"))

true falsefalse truetrue

Edge cases

• A date-time's year is read as written, like a date's.
• An int is not checked against the calendar's range: 0 and negative years answer by the same rule. A float with a whole value is taken as an int.

print(date.is_leap_year("2024-12-31T23:00:00-05:00"))print(date.is_leap_year(0), date.is_leap_year(-4), date.is_leap_year(2024.0))

truetrue true true

Errors

A string that is not a date, or a value that is neither an int nor a string, is a runtime error, not an error value.

print(date.is_leap_year("2024"))

line 1: `date.is_leap_year` expects a date or a date-time as argument 1, got "2024"

Chaining

print(range(2023, 2029) | filter(date.is_leap_year))print("2024-02-10" | date.is_leap_year)

[2024, 2028]true

See also

date.days_in_month, date.parts, date.add_years, date.end_of_month

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