Django snippets

list_check_template.html

<!--  check to see if atheletes is a list in a template   -->

{% if athlete_list %}
    Number of athletes: {{ athlete_list|length }}
{% else %}
    No athletes.
{% endif %}

NoneType check.txt

So how can I question a variable that is a NoneType?
Use is operator, like this
  ''
    if variable is None:
  ''
Why this works?

Since None is the sole singleton object of NoneType in Python, we can use is operator to check if a variable has None in it or not.

Quoting from is docs,

The operators is and is not test for object identity: x is y is true if and only if x and y are the same object. x is not y yields the inverse truth value.
Since there can be only one instance of None, is would be the preferred way to check None.


Comparisons to singletons like None should always be done with is or is not, never the equality operators.