Coding Grandmaster · project 32 of 46 · premium, free for now

Group by: totals per region

For every sale of at least minimum, add it to its region. Print one line per region (alphabetical) like east: total 360, average 180.0, orders 2.

Learn

Most questions about data are group-by questions: total sales per region, average mark per class. The pattern is a dictionary that starts empty; for each record you add to the entry for its group with totals.get(group, 0) + amount. Keep a second dictionary for counts and the average falls out as total ÷ count.

Your task

For every sale of at least minimum, add it to its region. Print one line per region (alphabetical) like east: total 360, average 180.0, orders 2.

Stretch challenge

Find which region has the highest average order, and which has the most orders.

← Records, filters and rankings Cleaning messy data →

Python

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Keep going in Coding Grandmaster

Records, filters and rankings

Keep the students whose score is at least cutoff, sort them by highest score (ties by name), print how many qualified, and print the first top of them as a numbered list.

Start →33

Cleaning messy data

Write fill_missing(values) that replaces each None with the mean of the other values rounded to 1 decimal place, and remove_duplicates(values) that keeps only the first of each repeated value in order. Print both results for the readings.

Start →34

Draw a bar chart

Draw one filled bar for each value, 40 wide and 15 times the value tall, 50 apart, starting at x = -150 along the line y = -100, using a different colour from the list for each.

Start →35

Draw a line chart

Draw an x axis and a y axis from the origin at (-150, -100), then plot the sales as dots (50 apart across, 5 times the value up) joined by lines.

Start →36

Capstone: a report table

Write grade(score) (A for 80 or more, B for 70 or more, otherwise C) and print the ranking, highest first, as an aligned table with a header, then the average (2 decimal places) and the name of the top scorer.

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Practise the idea

📊 Play Data Detective

Use mean, median and mode to describe a set of data and compare what each tells you.

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FAQ

Group by: totals per region: common questions

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