Python Iterator & Generator Programs with Solutions

20 iterator and generator programs: iter() and next(), custom iterator classes, generator functions with yield, generator expressions, infinite sequences, pipelines and itertools.

All programs

• #1Use iter() and next()
  Write a Python program that walks through a list with iter() and next().Easy
• #2A for loop by hand
  Write a Python program that rebuilds a for loop using while, iter() and next().Easy
• #3Countdown generator
  Write a generator that counts down from n to 1.Easy
• #4Even numbers generator
  Write a generator that yields even numbers up to a limit.Easy
• #5Fibonacci generator
  Write a generator that yields Fibonacci numbers, and take the first 10.Easy
• #6Generator expression of squares
  Write a Python program that sums squares with a generator expression.Easy
• #7Custom iterator class
  Write an iterator class that returns the characters of a word in reverse.Medium
• #8Iterable class with a generator method
  Write a class whose objects can be looped over many times.Easy
• #9Read a file lazily
  Write a generator that yields non-empty, stripped lines from a file.Easy
• #10Generator pipeline
  Write a pipeline of generators that reads numbers, keeps the even ones and squares them.Medium
• #11Split a list into chunks
  Write a generator that yields chunks of a given size.Easy
• #12Flatten nested lists with yield from
  Write a recursive generator that flattens nested lists.Medium
• #13Running total
  Write a generator that yields the running total of a list.Easy
• #14Unique id generator
  Write a generator that produces ids like TC-001, TC-002, …Easy
• #15Cycle through values
  Write a Python program that assigns browsers to 7 tests in rotation.Easy
• #16Iterators from zip and enumerate
  Write a Python program that shows zip and enumerate return iterators.Easy
• #17Generator vs list memory
  Write a Python program that compares the memory of a list and a generator of a million numbers.Easy
• #18Send values into a generator
  Write a generator that keeps a running average of values sent to it.Medium
• #19Take values while a condition holds
  Write a Python program that takes Fibonacci numbers while they are below 100.Easy
• #20Group consecutive items
  Write a Python program that groups log lines by level with itertools.groupby.Easy