Python Basics

1.1 Hands that type code, eyes that read it No problems

1.2 Your first run in the browser, no installation

• Printing text and calculated results Predict the output · Basic

1.3 The bare minimum about notebooks

• A cell that prints a name Predict the output · Basic
• The run order decides the value Predict the output · Basic
• A notebook that stops on Run all Code review · Basic

1.4 A map of this course The journey, the setup, and how to doubt No problems

1.5 [Pair coding with AI] Asking AI about setup problems

• An answer that says to reinstall Code review · Medium

2.1 Naming values Variables

• Changing the number of likes Predict the output · Basic

2.2 Numbers int and float

• Calculating again from the current value Predict the output · Basic

2.3 Strings A container for text

• + and * change with the data type Predict the output · Basic
• Telling numbers from text Predict the output · Basic

2.4 Indexing and slicing Taking strings apart

• Taking the city and the year out of a string Write code · Basic

2.5 f-strings Building output

• A sentence from an age and a year Write code · Basic

2.6 Type conversion Moving between int, float, and str

• Reviewing variables, slices, and data types Predict the output · Basic
• Reactions and the reaction rate Write code · Medium
• Fixing code that prints a name and an age Code review · Medium

2.7 [Pair coding with AI] Asking for string code Doubt the index boundaries

• A slice that is off by one Predict the output · Medium

3.1 Lists Many values in one container

• Printing a list and counting it Predict the output · Basic
• An empty list and one empty string Predict the output · Medium
• A line that reports the post count Write code · Basic

3.2 The same rules Indexing and slicing again

• Indexing and slicing a list Predict the output · Basic
• The first two and the last two Fill in the blanks · Medium
• View counts from the second to the fourth post Code review · Medium

3.3 Changing lists A new tool called methods

• Inserting, removing, and popping Predict the output · Medium
• Passing the turn in a question queue Write code · Medium
• An insert with the position and the value swapped Code review · Basic

3.4 Sorting and summarizing In place, or a new value?

• What append returns Predict the output · Basic
• A new sorted list that leaves the original alone Write code · Basic
• Fixing and summarizing a list of likes Write code · Medium
• Sorting that gives None Code review · Basic

3.5 Two names, one container Aliasing and copying

• The same list and a copied list Predict the output · Basic

3.6 Tuples Useful because they can't change

• Tuple items and variable names Predict the output · Basic
• Changing an item in a tuple Predict the output · Medium
• Taking the city and the year out of a tuple Write code · Basic

3.7 [Pair coding with AI] Asking for list code Copy or alias?

• Lists inside a list made by multiplying Predict the output · Challenge
• A new list without the spam account Code review · Medium

4.1 By name, not by number Dictionaries

• Finding ranks with number keys Predict the output · Basic
• Survey answers with the same key twice Predict the output · Medium
• Looking up follower counts with a name stored in a variable Write code · Medium

4.2 Updating dictionaries Adding, changing, and missing keys

• Looking up a missing key Predict the output · Basic
• The reaction rate of a post Write code · Medium

4.3 Looking inside dictionaries in, len, and three views

• Is data one of the values? Code review · Medium

4.4 Sets A container that refuses duplicates

• A set of viewers that drops duplicates Predict the output · Basic
• Collecting names, starting with empty braces Predict the output · Medium
• Removing and adding subscribers Fill in the blanks · Basic

4.5 Set operations and set() A tool for removing duplicates

• Comparing the tags of two posts Write code · Medium

4.6 A map of four containers Which one should you use?

• Follow pairs that have a direction Predict the output · Medium
• Summarizing post tags Write code · Medium

4.7 [Pair coding with AI] Asking for dictionary code Doubt missing keys

• A default value you cannot tell apart from 0 Code review · Medium

5.1 The two faces of division Quotient and remainder

• Six calculations with two numbers Write code · Basic

5.2 Order of operations Precedence and parentheses

• The order of calculation in an engagement score Predict the output · Basic
• Raising a variable that holds a negative number to a power Predict the output · Medium
• A growth rate with missing parentheses Code review · Medium

5.3 The language of true and false Comparison operators and Booleans

• Views that go past the goal Predict the output · Basic
• Several ways to ask whether two tag lists are the same Predict the output · Medium
• Updating the follower count and checking the goal Write code · Medium

5.4 Floats are approximations Before you ask whether two are equal

• Storing the rounded value back Predict the output · Basic
• Watch time just short of 0.8 Predict the output · Medium
• Checking the sum of response proportions Write code · Medium

5.5 Combining conditions and, or, not

• A check that mixes "and", "or", and "not" Predict the output · Challenge
• A condition for a range of views Fill in the blanks · Basic
• A condition that misses values outside the range Code review · Medium

5.6 Is it in there? in, not in, and a map of operators

• Is it in the list? Write code · Basic
• Does it meet both conditions? Write code · Basic
• A post summary and a condition check Write code · Challenge

5.7 [Pair coding with AI] Asking for calculations Doubt division and float comparisons

• Checking code that averages star ratings Predict the output · Medium
• Full pages and leftover posts Code review · Medium

6.1 What if if and indentation

• An assignment inside a skipped block Predict the output · Basic
• Activity points added separately Write code · Basic
• A congratulations message that slipped out of the block Code review · Basic

6.2 Otherwise Two branches with else

• A second check with the changed points Predict the output · Medium
• A title preview Write code · Medium
• Two thresholds with only one updated Code review · Medium

6.3 Many branches elif and letter grades

• Only the first true branch Predict the output · Basic
• A separate condition after the chain Predict the output · Medium
• Classifying post reactions by comment count Write code · Medium

6.4 Decided at the boundary Boundary values and overlapping conditions

• Matching an elif to its if by indentation Predict the output · Medium
• The boundaries between video lengths Fill in the blanks · Medium
• A new tier hidden by a wider condition Code review · Medium

6.5 Truthy and falsy What counts as true

• What "and" and "or" return Predict the output · Challenge
• Fixing a condition to fit its purpose Code review · Medium

6.6 [Pair coding with AI] Asking for branching code Doubt boundaries and missing cases

• A value that matches no branch Predict the output · Medium
• A views badge written by an AI Code review · Medium

7.1 Repeating for and range

• The end of range and the number of iterations Predict the output · Basic
• The step of range Predict the output · Basic
• The range end value for printing up to 8 Fill in the blanks · Basic
• Printing only the odd numbers Write code · Basic

7.2 Going through containers Looping over strings, lists, and dictionaries

• Looping over a dictionary with for Predict the output · Basic
• Printing only the likes at or above a threshold Write code · Basic
• Printing survey results Write code · Basic

7.3 Building up Accumulators and trace tables

• Where the running total is printed Predict the output · Basic
• Counting posts with 100 or more views Predict the output · Medium
• Comparing with the previous value Predict the output · Challenge
• Blanks in a sum of views Fill in the blanks · Basic
• The largest view count Write code · Basic
• The sum of multiples of 3 or 5 Write code · Basic
• The smallest value Write code · Medium
• The largest value and its position Write code · Medium
• The second-highest number of likes Write code · Medium
• Summarizing comment counts Write code · Medium
• Summarizing a list of posts Write code · Medium
• The second score when there are ties Write code · Challenge
• The names in first and second place Write code · Challenge
• Counting ratings of 4 stars or more Code review · Basic

7.4 While it is true while and infinite loops

• A while loop that keeps halving Predict the output · Medium
• When the while loop ends Predict the output · Medium
• The moment the sum first goes over 50 Predict the output · Medium
• The day followers reach 1000 Fill in the blanks · Medium
• The sum of the digits Write code · Medium
• The first day followers go over 500 Write code · Medium
• The digit sum and the number of digits Write code · Medium

7.5 Changing the flow break, continue, pass

• After the loop hits break Predict the output · Basic
• What happens with pass Predict the output · Basic
• continue and break Predict the output · Medium
• Skipping only 4 Fill in the blanks · Basic

7.6 Nested loops and the first math helper GCD and primes

• How many times the inner loop runs Predict the output · Medium
• Making pairs of two people Predict the output · Medium
• Predicting how many times code runs Predict the output · Medium
• A prime check that fails at the boundary Predict the output · Medium
• A blank in a star staircase Fill in the blanks · Basic
• Times tables that skip 2 and 5 Fill in the blanks · Medium
• Odd times tables in reverse order Fill in the blanks · Medium
• A five-line triangle of stars Write code · Basic
• Checking whether a number is prime Write code · Basic
• Finding all the divisors Write code · Basic
• Finding all the common divisors Write code · Basic
• An upside-down triangle Write code · Medium
• A triangle of numbers Write code · Medium
• Making a multiplication table Write code · Medium
• Collecting the primes in a range Write code · Medium
• How many primes are there? Write code · Medium
• The largest prime less than 100 Write code · Medium
• The greatest common divisor Write code · Medium
• The greatest common divisor and the least common multiple Write code · Medium
• The total of the odd times tables Write code · Medium
• Collecting only the odd products Write code · Medium
• A right-aligned triangle Write code · Challenge
• The tenth prime Write code · Challenge
• Code that finds only two primes Code review · Challenge
• Finding the sixth prime Code review · Challenge

7.7 [Pair coding with AI] Asking for loops Doubt range ends and infinite loops

• Splitting two classes into groups of the same size Fill in the blanks · Medium
• A sum of multiples of 5 that misses 60 Code review · Basic
• A loop that never looks at the last item Code review · Medium

8.1 Building parts Defining and calling functions

• Calling without an argument Predict the output · Basic
• A welcome message function Write code · Basic

8.2 Giving back return and None

• A function ends at return Predict the output · Basic
• Adding returned values Predict the output · Basic
• Nested calls Predict the output · Medium
• Returning the result Fill in the blanks · Basic
• How many times a digit appears Write code · Medium
• A function that returns the number of divisors Write code · Medium
• The most frequent number Write code · Challenge
• Rotating a list to the right Write code · Challenge

8.3 Handing over ingredients Positional and keyword arguments, and defaults

• Where each argument goes Predict the output · Medium
• Where the default value goes Predict the output · Medium
• Calling with a default value and keyword arguments Predict the output · Medium
• A default discount rate Fill in the blanks · Basic
• The sum of a range Write code · Medium
• A post summary split into functions Write code · Challenge

8.4 Returning several values Returning tuples and unpacking

• Two lists returned as a tuple Predict the output · Medium
• When there is one name too many Predict the output · Medium
• Receiving two values separately Fill in the blanks · Medium
• A function that summarizes a satisfaction survey Fill in the blanks · Medium
• Returning the maximum and the minimum together Write code · Medium
• A function that returns the total and the maximum together Write code · Medium

8.5 Inside and outside a function Local and global variables

• A parameter is a local variable too Predict the output · Medium
• A weekly view report Predict the output · Medium
• A bonus that keeps the original scores Code review · Medium
• The average video watch time Code review · Medium

8.6 The math helper as parts gcd and is_prime

• A prime-checking function Write code · Medium
• The fewest bags of rice Write code · Challenge
• An is_prime that gives wrong results Code review · Medium

8.7 [Pair coding with AI] Asking for functions The spec is the prompt; doubt functions that return nothing

• An engagement rate function that only prints Code review · Medium

9.1 Talking to your program input

• Numbers that come in as strings Predict the output · Basic
• A value that int() cannot convert Predict the output · Medium
• Where to convert to numbers Fill in the blanks · Basic
• An even or odd checker Write code · Basic
• A multiplication table printer Write code · Basic

9.2 Writing to a file open, write, close

• Text printed on the screen and text written to a file Predict the output · Basic
• Writing one per line and closing the file Fill in the blanks · Basic
• Passing a number straight to write() Code review · Basic

9.3 Reading a file read and looping over lines

• The newlines that readlines() keeps Predict the output · Medium
• Followers on the first and last days Fill in the blanks · Basic
• Counting survey answers Write code · Medium

9.4 Syntax that never forgets, and the contract of modes with, r/w/a/x

• A file opened with "w" and nothing written Predict the output · Medium
• The right mode for three files Fill in the blanks · Medium
• Reading a file outside the with block Code review · Medium

9.5 Where is it, and how is it written? Paths and encodings

• Two files with the same name Predict the output · Basic
• A file with the ad comments filtered out Write code · Medium
• Code with a leftover Colab Drive path Code review · Basic

9.6 The math helper remembers Saving and loading a list of primes

• Saving a tag list to a file and reading it back Write code · Challenge
• A save function that writes the newline first Code review · Medium

9.7 [Pair coding with AI] Asking for file code Doubt encodings, paths, and a missing close

• A record file that was never closed Predict the output · Medium
• Accented comments read with a different encoding Code review · Medium

10.1 Readable code What "Pythonic" means

• Swapping first and second place Predict the output · Basic
• A boundary that changed in a chained comparison Code review · Basic

10.2 A building loop in one line List comprehensions

• A list of hashtags and their lengths Predict the output · Basic
• Reversing survey scores Fill in the blanks · Basic
• Collecting only the authors from a list of posts Write code · Basic

10.3 Filtering and choosing Comprehensions with conditions

• An if at the end and an if-else at the front Predict the output · Basic
• Filtering out ad comments Write code · Medium
• View counts with the missing days dropped Code review · Medium

10.4 Index and value together enumerate

• Numbers counted from 1, and indexes Predict the output · Medium
• Numbers of the posts with 100 or more likes Write code · Medium
• A comment list where only the loop variable changed Code review · Medium

10.5 Walking side by side zip

• A zip with a missing partner Predict the output · Medium
• Checking the lengths before pairing Fill in the blanks · Medium
• Follower changes from yesterday to today Write code · Basic

10.6 Polishing the math helper Comprehensions and zip in practice

• Printing a summary of new followers Write code · Medium
• Days with more likes than average Write code · Challenge
• A label list that stops at assert Code review · Medium

10.7 [Pair coding with AI] "Make it Pythonic" A hard-to-read one-liner is not an improvement

• Three branches packed into one line Predict the output · Medium
• Engagement rates from swapped pairs Code review · Medium

11.1 Data and behavior together Thinking in objects

• Authors and likes that no longer match Predict the output · Basic
• A post bundled in a dictionary, with functions outside Write code · Basic

11.2 Drawing the blueprint class, __init__, self

• A method call with one extra value Predict the output · Medium
• Blanks in a song blueprint Fill in the blanks · Basic
• A post that remembers its likes and comments Write code · Medium

11.3 Methods that change state Deposits and withdrawals

• Someone who votes twice Predict the output · Medium
• A stamp card with a reward for ten stamps Write code · Challenge
• A follower count that never goes down Code review · Basic

11.4 Shared by all, owned by each Class variables and __str__

• The class's default goal and one person's goal Predict the output · Medium
• A number and a list kept in the class Predict the output · Challenge
• Members numbered in the order they join Write code · Medium

11.5 When you need a class State justifies the design

• A method that only the child class has Predict the output · Medium
• Calling a method of the same class Code review · Basic

11.6 The math helper evolves PrimeFinder, which remembers primes

• A cache that remembers tags already counted Fill in the blanks · Medium
• Counting the days posted in a row Write code · Challenge

11.7 [Pair coding with AI] Asking for class design Doubt overdesign

• A like total that grows with every call Code review · Medium

12.1 Graduating from notebooks .py files and the terminal

• The lines a script shows Predict the output · Basic
• A script in a different order from the cells Predict the output · Medium
• A summary that throws away returned values Code review · Basic

12.2 import Bringing in parts others made

• The range randint draws from Predict the output · Medium
• A square grid that fits all the photos Write code · Medium
• Adjusting scores without touching the original Write code · Medium

12.3 from, as, and the star Reading import statements

• A variable that overwrote a module name Predict the output · Medium
• A title overwritten by a star import Code review · Medium

12.4 Making your own module gcdlcm.py and the two faces of a file

• A line that prints just from importing Predict the output · Medium
• Using values from a settings module Fill in the blanks · Basic
• An old copy that hides the module's function Code review · Medium

12.5 Packages The math helper, ready to share

• The names of modules inside a package Predict the output · Challenge
• Drawing bars with a survey package Write code · Medium
• The import after moving a file into a folder Code review · Medium

12.6 [Pair coding with AI] Asking for library suggestions Check for modules that don't exist

• A missing function in a real module Predict the output · Basic
• Built-in functions instead of a module that does not exist Code review · Medium

13.1 Reading the red text to the end Tracebacks

• Adding up likes with a string mixed in Predict the output · Basic
• Where the follower lookup stopped Predict the output · Medium

13.2 A program that doesn't crash try and except

• A response counted before the error Predict the output · Medium
• Failures you can check for and failures you find by trying Fill in the blanks · Basic
• None when the text does not convert to an integer Write code · Basic

13.3 What to catch Error families and wide nets

• The message caught with as e Predict the output · Medium
• A different message for each failure Write code · Medium
• The wrong error name Code review · Basic

13.4 Cleaning up and refusing honestly finally, else, raise

• A finally that runs before the return Predict the output · Medium
• An error raised again inside except Predict the output · Challenge
• Rejecting star ratings out of range Write code · Medium

13.5 The math helper gets sturdy Three layers of armor

• Catching a rejection raised by a helper function Write code · Medium
• When the settings file is missing and when it is broken Write code · Medium

13.6 [Pair coding with AI] Asking to add exception handling Doubt handling that silences errors

• A false message left by a wide net Predict the output · Medium
• A search for the most likes that stops halfway Code review · Medium