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Python datetime and days_in_month (#44)
* minimal first pass * minor updates * add days_in_month ncl page and index entry * add raw ncl, receipt file, and update main ncl entry * add note about input types * fix typo, add days in month section to datetime.ipynb * change maxdepth receipts page * remove filler content under receipts * Update applications/date_time/datetime.ipynb Co-authored-by: Katelyn FitzGerald <[email protected]> * Update applications/date_time/datetime.ipynb Co-authored-by: Katelyn FitzGerald <[email protected]> * Update applications/date_time/datetime.ipynb Co-authored-by: Katelyn FitzGerald <[email protected]> * Update applications/date_time/datetime.ipynb Co-authored-by: Katelyn FitzGerald <[email protected]> * Update applications/date_time/datetime.ipynb Co-authored-by: Katelyn FitzGerald <[email protected]> * dateS and timeS * remove real python link * dateS and timeS * remove card link to subsection page * remove rest of the card header links * convert grab and go to python block w/ output * another dateS adn timeS * top level toc ncl -> ncl to python * add links to overview * reword for cftime input caveat section * reword for cftime input caveat section * Update ncl/ncl_entries/days_in_month.ipynb Co-authored-by: Andy McKeen <[email protected]> --------- Co-authored-by: Katelyn FitzGerald <[email protected]> Co-authored-by: Andy McKeen <[email protected]>
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‎applications/applications.rst

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.. grid:: 1
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.. card:: :ref:`applications_datetime`
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.. card:: Dates and Times
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- `Working with Date and Time <applications/date_time/datetime.ipynb>`_
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.. card:: :ref:`applications_plot_types`
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.. card:: Plot Types
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.. grid-item::
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.. grid:: 1
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.. card:: :ref:`applications_data_analysis`
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.. card:: Data Analysis
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.. grid-item::
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‎applications/date_time/NCL_datetime.ipynb

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‎applications/date_time/date_time.rst

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.. _applications_datetime:
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Date and Time
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=============
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Dates and Times
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===============
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.. toctree::
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:maxdepth: 1

‎applications/date_time/datetime.ipynb

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{
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"cells": [
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{
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"cell_type": "markdown",
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"id": "b53cacffa29d30a6",
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"metadata": {},
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"source": "# Working with Dates and Times"
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},
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{
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"cell_type": "markdown",
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"id": "783a656d272204c2",
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"metadata": {},
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"source": [
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"## Overview\n",
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"Working with dates and times in Python is a common task in geoscience workflows. This notebook will cover:\n",
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"- Working with the [`datetime`](docs.python.org/3/library/datetime.html) module from the Python Standard Library\n",
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"- [`cftime`](unidata.github.io/cftime/index.html), [CF Conventions](cfconventions.org), and how they are related to working with geoscience data\n",
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"- A resource guide to point you to more detailed information depending on your use case"
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]
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},
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{
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"cell_type": "markdown",
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"id": "13edacb9510e559e",
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"metadata": {},
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"source": [
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"## The `datetime` module\n",
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"From the [module's documentation](https://docs.python.org/3/library/datetime.html):\n",
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"\n",
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"> The `datetime` module supplies classes for manipulating dates and times.\n",
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">\n",
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"> While date and time arithmetic is supported, the focus of the implementation is on efficient attribute extraction for output formatting and manipulation."
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]
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},
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{
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"cell_type": "code",
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"id": "2092ca5d86a3a24b",
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"metadata": {
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"ExecuteTime": {
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"end_time": "2024-06-03T04:44:37.784336Z",
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"start_time": "2024-06-03T04:44:37.781266Z"
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}
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},
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"source": [
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"import datetime\n",
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"\n",
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"today = datetime.date.today()\n",
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"print(f\"datetime.date.today() -> \\t {today}\")\n",
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"now = datetime.datetime.now()\n",
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"print(f\"datetime.datetime.now() -> \\t {now}\")"
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],
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"outputs": [
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{
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"name": "stdout",
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"output_type": "stream",
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"text": [
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"datetime.date.today() -> \t 2024-06-02\n",
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"datetime.datetime.now() -> \t 2024-06-02 22:44:37.783255\n"
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]
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}
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],
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"execution_count": 1
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},
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{
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"cell_type": "markdown",
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"id": "6368d2ab290b3d1",
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"metadata": {},
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"source": [
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"### `strftime()`\n",
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"\n",
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"You can use [`strftime()`](https://docs.python.org/3/library/datetime.html#datetime.datetime.strftime) to parse and format these date objects.To see all formatting options, see the [full list of format codes](https://docs.python.org/3/library/datetime.html#format-codes)."
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]
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},
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{
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"cell_type": "code",
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"id": "1d18147498a434eb",
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"metadata": {
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"ExecuteTime": {
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"end_time": "2024-06-03T04:44:37.787843Z",
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"start_time": "2024-06-03T04:44:37.785520Z"
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}
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},
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"source": [
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"# print just the year\n",
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"print(\"now.strftime('%Y')\")\n",
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"print(now.strftime(\"%Y\"))\n",
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"print()\n",
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"\n",
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"# print weekday, month, day, year, 12h time, and AM/PM\n",
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"print(\"now.strftime('%A, %B %d %Y %I:%M:%S %p')\")\n",
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"print(now.strftime(\"%A, %B %d %Y %I:%M:%S %p\"))\n",
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"print()\n",
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"\n",
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"# use a shorter version to produce \"locale appropriate\" date and time\n",
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"print(\"now.strftime('%c')\")\n",
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"print(now.strftime(\"%c\"))"
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],
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"outputs": [
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{
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"name": "stdout",
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"output_type": "stream",
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"text": [
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"now.strftime('%Y')\n",
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"2024\n",
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"\n",
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"now.strftime('%A, %B %d %Y %I:%M:%S %p')\n",
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"Sunday, June 02 2024 10:44:37 PM\n",
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"\n",
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"now.strftime('%c')\n",
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"Sun Jun 2 22:44:37 2024\n"
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]
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}
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],
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"execution_count": 2
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},
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{
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"cell_type": "markdown",
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"id": "d176a3090c4730eb",
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"source": "These functions use a [propeleptic Gregorian](https://en.wikipedia.org/wiki/Proleptic_Gregorian_calendar) calendar, though, which is not always sufficient for working with geoscience data."
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},
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{
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"cell_type": "markdown",
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"source": "# Working with Date and Time",
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"id": "b53cacffa29d30a6"
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"id": "c8a19ab9f50212c5",
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"metadata": {},
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"source": [
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"## cftime\n",
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"\n",
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"[`cftime`](https://unidata.github.io/cftime/) is another library for working with dates and times in Python that conforms to the [Climate and Forecasting (CF) metadata conventions](https://cfconventions.org/cf-conventions/cf-conventions#time-coordinate).\n",
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"\n",
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"Importantly, `cftime` supports all the calendars defined in the CF conventions, including `gregorian` or `standard`, which is the mixed Gregorian/Julian calendar defined by [Udunits](https://www.unidata.ucar.edu/software/udunits/), `proleptic_gregorian`, `noleap` or `365_day`, `all_leap` or `366_day`, `360_day`, and `julian`.\n",
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"\n",
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"`cftime` is often useful for working with geoscience data and can be used with [`xarray`](https://docs.xarray.dev/en/stable/generated/xarray.CFTimeIndex.html)."
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]
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},
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"cell_type": "markdown",
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"source": "## The datetime module",
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"id": "13edacb9510e559e"
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"source": "## Specific Use Cases",
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"id": "a710537046d5a159"
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"metadata": {},
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"cell_type": "markdown",
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"source": [
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"### Calculating the number of days in a month\n",
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"To calculate the number of days in a month, use [`cftime.datetime().daysinmonth`](https://unidata.github.io/cftime/api.html#cftime.datetime)."
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],
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"id": "de2a66ba6d34497d"
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},
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{
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"metadata": {
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"ExecuteTime": {
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"end_time": "2024-06-03T04:44:37.861353Z",
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"start_time": "2024-06-03T04:44:37.788458Z"
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}
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},
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"cell_type": "code",
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"outputs": [],
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"execution_count": null,
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"source": "",
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"id": "bc54610955d8ef71"
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"source": [
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"import cftime\n",
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"\n",
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"day = 1\n",
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"month = 6\n",
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"year = 2024\n",
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"\n",
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"date = cftime.datetime(year, month, day, calendar=\"standard\").daysinmonth\n",
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"date"
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],
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"id": "f0390a82422e4913",
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"outputs": [
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{
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"data": {
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"text/plain": [
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"30"
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]
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},
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"execution_count": 3,
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"metadata": {},
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"output_type": "execute_result"
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}
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],
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"execution_count": 3
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},
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{
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"cell_type": "markdown",
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"id": "1d434857c1cd81d1",
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"metadata": {},
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"source": [
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"## Curated Resources\n",
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"\n",
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"To learn more about working with dates and times in Python, we suggest:\n",
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"- the Project Pythia Foundations chapter titled [Times and Dates in Python](https://foundations.projectpythia.org/core/datetime/datetime.html)\n",
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"- this Xarray [documentation page on timeseries data](https://docs.xarray.dev/en/latest/user-guide/time-series.html)\n",
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"- the [\"How to handle time series data with ease\"](https://pandas.pydata.org/docs/getting_started/intro_tutorials/09_timeseries.html) tutorial if you're working with `pandas`"
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]
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}
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],
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"metadata": {

‎index.rst

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.. toctree::
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:hidden:
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:caption: NCL
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:caption: NCL to Python
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NCL Index <ncl/ncl_index/ncl_index>
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NCL Applications <applications/ncl_applications.rst>
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NCL Applications <ncl/ncl_entries/ncl_entries.rst>
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.. toctree::
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:maxdepth: 2

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