How to Calculate Weighted Averages in a Python Dictionary Using List Comprehension

Learn how to use Python's features to calculate a weighted average of students' grades stored in a dictionary. Follow this easy guide for beginners!
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How to Calculate Weighted Averages in a Python Dictionary Using List Comprehension

If you're new to programming in Python and want to manage student grades effectively, you may find yourself needing to calculate weighted averages. This is particularly useful when you have a dictionary structured with students' names and their corresponding scores. In this guide, we will explore how to accomplish this task through list comprehension, a powerful and concise way to create lists in Python.

Introduction to the Problem

Let’s say you have a dictionary containing a list of students along with their scores on three different assessments. Your goal is to compute a fourth field called average, which represents the weighted average of the students' scores based on predefined weights. The weights for each score are as follows:

Score 1: 20%

Score 2: 30%

Score 3: 50%

You want your final output to look like this:

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What We're Working With

Input Dictionary

Here's the initial input that contains the scores:

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Expected Output

Your task is to add a fifth key, avg, which should contain the calculated averages:

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Step-by-Step Solution

Step 1: Initialize the Average List

First, you need to create a list that will hold the average scores. This is where we will collect the results:

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Step 2: Iterate Through Each Student

You can use a for-loop to iterate over each student in the scores dictionary. During each iteration, you'll extract the current student's scores:

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Step 3: Calculate the Weighted Average

For each student, calculate the weighted average using the formula provided. Here's how you can do that:

[[See Video to Reveal this Text or Code Snippet]]

Step 4: Add the Average to the Dictionary

Once all averages are calculated, you can add the avg list to your original scores dictionary:

[[See Video to Reveal this Text or Code Snippet]]

Full Code

Here's how the complete code will look:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

Calculating weighted averages in a dictionary using list comprehension in Python is straightforward once you break it down into manageable steps. By following this guide, you can easily manage student scores and compute their average, making your coding journey just a bit smoother. Happy coding!

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