Jinja list comprehension examples ("Them Apples")

Practice writing list comprehension, using Jinja, to create a new list from existing list data.

Module Overview

💡 Let's explore list comprehension with two examples, focusing on how the output (first part) and condition (last part, optional) can be used.

Video (4:56 Minutes)

Picture this: a basket of apples labeled "them_apples." Each apple has attributes like color, shape, and brand name (e.g., Granny Smith, Red Delicious). We’ll use these details to build two different lists.

Example 1: Apple Names

We want a list of the apple brand names. Here's how the list comprehension breaks down:

• Output: The specific attribute we want is the apple's name. So, we use apple.name.

• For Loop: Loop through each apple with for apple in CTX.them_apples.

• Condition: No condition needed here.

The result is a list of brand names like Pink Lady, Honeycrisp, and Jazz, stored in CTX.apple_names. You’ll learn more about storing lists in the lesson on Creating an Option Generator Workflow.

Example 2: Down With Red Delicious

This time, let's filter a list by the attribute "color" to create a new list that excludes red apples.

• Output: We want the whole apple this time, so we use apple.

• For Loop: Same as before, for apple in CTX.them_apples.

• Condition: Only include apples with the colors pink or green, by writing if "green" in apple.color or if "pink" in apple.color.

Alternative methods for the condition could be:

• if "red" not in apple.color

• if "Red Delicious" not in apple.name

This gives us a new list of only pink and green apples, stored in CTX.best_apples.

Action Items

• Practice the Lunch Menu exercises that use list comprehension.

• Post further questions about list comprehension in the #cluck-u Rewst Discord channel to get help from professors and peers!

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