Resolve “List Object Has No Attribute Length” in Ansible

Fix the common Ansible error using Jinja2 filters for accurate list handling.

The error message list object has no attribute length typically occurs in Ansible when attempting to use the attribute length on a list. In Ansible, the Jinja2 templating language is used, and lists don’t have a length attribute. Instead, you should use the length filter to get the length of a list.

Here’s how to resolve this issue:

Problem

You may be trying to get the length of a list like this:

- debug:
    msg: "{{ my_list.length }}"

This will cause an error because lists in Jinja2 don’t have a length attribute.

Solution

Instead, use the length filter:

- debug:
    msg: "{{ my_list | length }}"

Example

Suppose my_list is defined as follows:

my_list:
  - item1
  - item2
  - item3

Then, to get the length of my_list, you would use:

- debug:
    msg: "The length of my_list is {{ my_list | length }}"

Explanation

• my_list | length applies the length filter to my_list, which…