How to Get length of a list in a jinja2

Jinja2 is a popular templating engine for Python, which allows developers to create dynamic web pages by combining HTML templates with data from their Python code. Jinja2 provides a wide range of filters and functions that can be used to manipulate data inside jinja2 templates, including functions for working with lists.

Jinja2 provides a built-in function called length that can be used to retrieve the number of items in a list.

Example: Get the Length of a List with jinja2

In this example, we first define a variable called my_list that contains a list of integers. We then use the length filter to retrieve the length of the list and output it to the template.

Check: Get the Median of a List in Python

{% set my_list = [1, 2, 3, 4, 5] %}
The length of my_list is {{ my_list|length }}.

(|) Character to get the length of List

We use the | character to apply the length filter to the my_list variable. This is a common syntax in Jinja2 for applying filters to variables.

In this example, we first define a variable called names that contains a list of strings. We then use the length filter to retrieve the length of the list and use it in an if statement to check if there are more than three names in the list. Depending on the result of the if statement, we output a different message to the template.

{% set names = ['Alice', 'Bob', 'Charlie', 'Dave'] %}
{% if names|length > 3 %}
  There are more than three names in the list.
{% else %}
  There are three or fewer names in the list.
{% endif %}

Example: Get length of a List in Python Jinja2

The length of [1, 2, 3, 4, 5] is {{ [1, 2, 3, 4, 5]|length }}.

Summary and Conclusion

In this article, we have discussed how to get the length of a list in the Python jinja2 template. I hope this article was helpful. Please share it with your friends.

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