Housekeeping There will be a quiz on the basics of functions on Tues and Wed, depending on your block.

Let's shoot for the end of the week for to_the_moon.py and string_play.py. The first is a very simple exercise in input and output and the second can be done by using Python's string methods pretty much "straight out of the bottle."

The random Library

This is the last item in the boss statements chapter. It's fabulous for making games and for doing stochastic simulation when combined with looping. We will do a brief tour of some of its services

Shuffling a List

Random Sampling from a List

Flipping a Coin

Magic 8 Ball

Here is a list with its replies.

replies = ["As I see it, yes.", "Ask again later.", "Better not tell you now.", "Cannot predict now.", "Concentrate and ask again.", "Don't count on it.", "It is certain.", "It is decidedly so."] 

Generating Pseudorandom Integers

Roll a pair of dice. Roll an exotic die from an RPG, say 20-sided

Generating Uniform Variates

Iterables and Definite Repetition

Hummingbird iterating through a collection of flowers

for flower in inflorensce:
    suck_nectar(flower)
    pollinate(flower)

What is an iterable? For now, think this way. Iterables are "food" for for loops. Iterables contain an object called an iterator, which causes the elements to be visited in succession to a for loop to act upon. Here is a field guide to iterators for our favorite types. One nice thing about iterators: they do not change the collection they are walking through.

• strings This iterator walks through a string one character at a time in index order.
• lists and tuples Their iterators walk through one element at a time in index order.
• sets The iterator walks through the set in no particular order.
• dictionaries The iterator walks the keys of a dictionary one key at a time in no particular order.
• file objects The iterator walks through a file one line at a time.

Here are some other iterables.

• range objects
• dictionary_keys object
• dictionary_values object

We will do tons of examples.

enumerate and reversed are very handy for altering the behavior of iterators.