Date-Time Comparisons

Date-Time Comparisons in Jinja

Date and time manipulations are a crucial aspect of template engines like Jinja, especially when working with dynamic content and automation. In this article, we will explore various date-time comparisons and operations using Jinja's built-in functions.

Formatting Current Date and Time

Often, you need to display the current date and time in a specific format. Jinja provides the now filter for this purpose. Here's how you can format the current date and time in UTC:

now_formatted -> {% now 'utc', '%Y-%m-%dT%H:%M:%SZ' %}

This will output the current UTC date and time in the format 'YYYY-MM-DDTHH:MM:SSZ'.

Calculating Dates

Jinja allows you to perform date calculations easily. For example, to get the date and time from two days ago in the same format as above:

two_days_ago -> {% now 'utc' - 'days=2', '%Y-%m-%dT%H:%M:%SZ' %}

This code subtracts two days from the current UTC date and time and formats the result accordingly.

Formatting Dates Using format_datetime

The format_datetime filter allows you to format a datetime object to a specified string format. In this example, we determine the day of the week for a specific date:

It was a {{ ["Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday"]["2022-07-04T11:38:00" | format_datetime("%w") | int] }}

Here, we convert '2022-07-04T11:38:00' to a datetime object and then extract the day of the week as an integer, which is used as an index to fetch the corresponding day name.

Loading Date from a String

Sometimes, you may have a date in string format and need to convert it into a datetime object. The load_datetime filter serves this purpose. Here's an example of loading a date from the format '06-09-2022':

{{ "06-09-2022" | load_datetime("%m-%d-%Y") }}

This code converts the string '06-09-2022' to a datetime object.

Date Arithmetic with time_delta

Jinja provides the time_delta filter to add or subtract units from a datetime object. In this case, we subtract 30 days from a loaded datetime object and format the result:

{{ "06-09-2022" | load_datetime("%m-%d-%Y") | time_delta(days=-30) | format_datetime("%B %d, %Y") }}

The code first converts '06-09-2022' to a datetime object, then subtracts 30 days, and finally formats the result in the 'Month Day, Year' format.

Helpful Resources

When working with date formats, it's essential to be familiar with the format codes. For reference, you can visit the strftime.org website, which provides a comprehensive list of format codes for various date and time components.