![]() ![]() The map filter applies a filter on a sequence of objects or looks up an attribute. Once you select the data, pass it to the map filter. You're selecting the members key of the dictionary if the members key is "defined." In this case you know it is, so you can expect data to be returned. name: Show what type of data the bands variable is made up ofįor the next task, list all members of all bands. name: Show what type of variable bands is Simply put, this shows you're dealing with a list of dictionaries. The second task should show the bands variable is made up of dictionaries. In the first task, you should see that the bands variable itself is a list. Next, create a set of tasks that show what kind of data you are dealing with. Within the function any(), a list comprehension will loop through the list and check if the value of interest exists within the value of each dictionary in the. As you put the playbook together, you'll begin to see how to select data from the variable. The variable bands is a list of dictionaries that will be used in the example.yml playbook. Get started with filtersįirst, create a variable called bands. Using Jinja filters mitigates the immediate need for external collections to extract data from lists of dictionaries. You may not have the luxury of adding collections on the fly without some level of approval beforehand. Thus, it is not natively installed with Ansible. The json_query module, however, is part of the community.general collection. Since selectattr() and map() are Jinja filters, you don't need to add anything to your server if Ansible is installed. While some Ansible users prefer to use the json_query filter, I personally prefer to use Jinja's selectattr() and map() filters. In this article, I focus on selectattr() and map(). This approach is intuitive because it loops over each item in the list (unless explicitly stopped). A for loop allows you to iterate over an interable object (like a list) and perform a given action. To be fair, there are a lot of Jinja filters. One of the simplest ways to loop over a list in Python is by using a for loop. Learning how to use these filters properly will take your Ansible skills to the next level. This is useful when you have lists of objects but you are interested in only a certain value. Sometimes you may need to iterate through a dictionary in Python but want to do it in sorted order. map() applies a filter on a sequence of objects or looks up an attribute.selectattr() filters a sequence of objects by applying a test to the specified attribute of each object and only selecting the objects when the test succeeds.The Jinja documentation explains the filters like so: Jinja is powerful templating language that has two filters that are ideal for extracting data from lists of dictionaries. This is where Jinja filtering comes in handy. On occasion, the data you're working with is actually a list of dictionaries. When you're working with Ansible, you typically work with lists and dictionaries. Automate Red Hat Enterprise Linux with Ansible and Satellite.Ansible Automation Platform trial subscription.A system administrator's guide to IT automation.Ansible Automation Platform beginner's guide.Skip to bottom of list Skip to the bottom of list ![]()
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