Loop Through a Dictionary: Count and Total
Python Programming 2 Grades 9–12 3-day lesson 25 deliverables Teach students to count and add up data in Python with a dictionary and a loop. Students tally field trip votes by hand, trace a loop that counts them and use .get() with a default for a new key. They clean text, count the words in a line, find the most common word with a loop over .items() and add up snack sales by item.
● Instant download · Lifetime access · Editable & print-ready
Print + digitalPDF, PowerPoint, Word & Google
Answer keysA key for every page
Built-in assessmentExit tickets + lesson quiz
45-minute daysEvery day planned and timed
Short coding levels practice this lesson in CodeGrove, our code lab that runs in the browser. Students write the program, run it and check it, with no account and nothing to install. Use them with the lesson or as practice later.
See the levelsWhat does this lesson cover?
Students may write a long chain of if lines to count each choice, or crash when a new key shows up. This lesson uses one dictionary and one loop for any number of keys. Students also clean the text first, so The and the count as one word.
The try-it on Day 1, the lab on Day 2 and the quiz task on Day 3 run online in CodeGrove, our in-browser code lab, so students need a computer or tablet on those days. The Word Counter level practices counting the words in a line of text with a dictionary and .get(), then finding the most common word with a loop over .items(). CodeGrove is free, with no accounts, sign-ins or installs.
Word Counter
Students clean and count the words in a line of text in CodeGrove, find the most common word and print a table from A to Z.
Everything that's included
00 Start Here
- READ FIRST: every file in the lesson and when you use it
- Teacher Guide and Pacing: the plan for each day, what to print and how to grade
- Skills map: which standards each day teaches
01 Present
- One editable PowerPoint deck for all three days, 22 slides, with speaker notes
- Slide script: the speaker notes, printed
- Bell ringers: a short warm-up for each day
02 Student Handouts
- Guided notes: one packet for all three days, in PDF and editable Word. Students fill in the blanks during the slides, with the word bank on the page
- Vocab slip: the lesson's words and what they mean, on one page
03 Labs
- Word Counter: students clean and count the words in a line of text in CodeGrove, find the most common word and print a table from A to Z
04 Activities
- Tally by Hand: students tally field trip votes by hand, trace a loop that counts them and practice counting in CodeGrove
- Quiz task: students add up snack sales by item in CodeGrove, working alone, and then take the lesson quiz
05 Assessment
- Exit tickets: quick questions that show who needs more help
- Lesson quiz: 8 multiple-choice questions and 2 written answers about all three days, on paper
06 Answer Keys
- 5 answer key files: a key for each day (its bell ringer, notes and exit ticket) and the activity and lab keys, plus the quiz key
Digital: Google Forms™ + Google Slides™
- 4 Google Forms™ of the exit tickets and the quiz, ready to copy into your Drive
- The multiple choice grades itself, and you grade the written answers
- A Google Slides™ copy of the deck, with the same slides and speaker notes, for Google Classroom™
- Give a Form that asks students to read code only on school-managed Chromebooks in locked mode, and use the paper version on other devices
Online: CodeGrove
- In CodeGrove: the lab on Day 2 (Word Counter) and the quiz task on Day 3, on a computer or tablet for each student
- A try-it on Day 1: students practice the new code in CodeGrove, and nothing is turned in
- Free to use, with no accounts, sign-ins or installs
Why teachers love this lesson
One loop counts any number of keysThe line counts.get(k, 0) + 1 counts a key, even a new one. Students do not need a separate variable for each choice.
Clean data gives honest countsStudents clean the text before they split it. Then a loop keeps the best so far to find the most common word, and sorted(d) lists the keys from A to Z.
Print and digitalEvery page is a print-ready PDF, and the Google Forms™ and Google Slides™ let you teach the same lesson in Google Classroom™.
Real online labsStudents write and run real Python in CodeGrove, our in-browser code lab, on a computer or tablet, with no accounts or installs.
A key for every pageEvery day has its own answer key, and every written question has a sample answer and what to look for.
Every day fits a 45-minute classEach day's plan is timed activity by activity against real reading and writing speeds.
What Teachers Say
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How do I get the files after I buy?
Instant download right after checkout: PowerPoint and Word files you can edit, print-ready PDFs, and links that copy the Google Forms™ and Google Slides™ into your Drive.
Can I buy the whole unit or course instead?
Yes. This lesson is part of the Unit 4 bundle and the complete Python Programming 2 course. Both cost less than buying the lessons one at a time.
Is this AP Computer Science?
No. It is a full-year, non-AP second course in Python for grades 9 to 12. For AP, see our AP Computer Science A and AP CSP courses.
What should students know before this lesson?
Students know .get(), list methods, sorted(), and format specs like :<8.
Do students need computers?
Yes, on the CodeGrove days. Each student needs a computer or tablet that's online, and CodeGrove needs no account or install. The bell ringers, notes, exit tickets and quiz are on paper.
What formats are the files in?
Every page is a print-ready PDF. The slides are an editable PowerPoint and the guided notes an editable Word file. The exit tickets and the quiz also come as Google Forms™, and the deck as Google Slides™.
Which standards does it cover?
Written for Florida's Intermediate Programming course (9007220). The skills map in the lesson shows which standards each day teaches.