diff --git a/doc/source/reference/arrays.datetime.rst b/doc/source/reference/arrays.datetime.rst index 835f4431ed8f..08caaf23113b 100644 --- a/doc/source/reference/arrays.datetime.rst +++ b/doc/source/reference/arrays.datetime.rst @@ -19,7 +19,8 @@ Basic Datetimes The most basic way to create datetimes is from strings in ISO 8601 date or datetime format. The unit for internal storage is automatically selected from the form of the string, and can -be either a "date unit" or a "time unit". The date units are years ('Y'), +be either a :ref:`date unit ` or a +:ref:`time unit `. The date units are years ('Y'), months ('M'), weeks ('W'), and days ('D'), while the time units are hours ('h'), minutes ('m'), seconds ('s'), milliseconds ('ms'), and more SI-prefix seconds-based units. @@ -97,7 +98,8 @@ because the moment of time is still being represented exactly. True An important exception to this rule is between datetimes with -"date units" and datetimes with "time units". This is because this kind +:ref:`date units ` and datetimes with +:ref:`time units `. This is because this kind of conversion generally requires a choice of timezone and particular time of day on the given date. @@ -167,15 +169,30 @@ mode which allows for accounting of leap-seconds is proposed), with a epoch of 1970-01-01T00:00Z. This means the supported dates are always a symmetric interval around 1970. +Here are the date units: + +.. _arrays.dtypes.dateunits: + +======== ================ ======================= ========================== + Date unit Time span Time span (years) +------------------------- ----------------------- -------------------------- + Code Meaning Relative Time Absolute Time +======== ================ ======================= ========================== + Y year +- 9.2e18 years [9.2e18 BC, 9.2e18 AD] + M month +- 7.6e17 years [7.6e17 BC, 7.6e17 AD] + W week +- 1.7e17 years [1.7e17 BC, 1.7e17 AD] + D day +- 2.5e16 years [2.5e16 BC, 2.5e16 AD] +======== ================ ======================= ========================== + +And here are the time units: + +.. _arrays.dtypes.timeunits: + ======== ================ ======================= ========================== - Date or Time unit Time span Time span (years) + Time unit Time span Time span (years) ------------------------- ----------------------- -------------------------- Code Meaning Relative Time Absolute Time ======== ================ ======================= ========================== - Y year (date) +- 9.2e18 years [9.2e18 BC, 9.2e18 AD] - M month (date) +- 7.6e17 years [7.6e17 BC, 7.6e17 AD] - W week (date) +- 1.7e17 years [1.7e17 BC, 1.7e17 AD] - D day (date) +- 2.5e16 years [2.5e16 BC, 2.5e16 AD] h hour +- 1.0e15 years [1.0e15 BC, 1.0e15 AD] m minute +- 1.7e13 years [1.7e13 BC, 1.7e13 AD] s second +- 2.9e12 years [ 2.9e9 BC, 2.9e9 AD]