When Django QuerySets are evaluated?

django-queryset-evaluation.note

When QuerySets are evaluated

You can concatenate as many filters as you like to a QuerySet, and you will not hit the database until the QuerySet is evaluated. QuerySets are only evaluated in the following cases:

    The first time you iterate over them
    When you slice them, for instance, Post.objects.all()[:3]
    When you pickle or cache them
    When you call repr() or len() on them
    When you explicitly call list() on them
    When you test them in a statement, such as bool(), or , and, or if

Source: https://www.oreilly.com/library/view/django-2-by/9781788472487/c0d84fbe-ed96-47e5-b185-cf86335da8d6.xhtml