Everyone Can Code! Tutorial Script

ecc_examples.py

import random
import turtle

# 1. Hello World!

# This is designed as a first introduction to the language.
# One print statement and done!

def print_hello_world():
	print "Hello, World!"

# 2. Say My Name, Say My Name (Beyonce, anyone?)

# This is designed as a first-stab at user input.
# Asks the user what their name is, and says hello to them.

def say_hello_back():
	print "Hello, %s!" % (raw_input('What is your name? '))

# 3. Valve Say Whaaaaat? (Heh, get it? Because flow control...)

# This is designed as a basic introduction to flow control.
# It builds on the previous two exercises.

def say_something_smart():
	age = int(raw_input('How old are you? '))
	if (age > 30):
		print "You are very wise."
	elif (age < 20):
		print "You have much to learn, grasshopper."
	else:
		print "You are just a hooligan!"

# 4. Pop Quiz!

# A very simple quiz question generator for arithmetic.
# Introduces the idea of the "standard library" by using the random number
# generator. This returns boolean so we may use it in the next example.

def quiz_me():
	a = random.randint(1, 10)
	b = random.randint(1, 10)

	answer = int(raw_input('What is %d + %d? ' % (a, b)))

	if (a + b == answer):
		print "Correct!"
		return True
	else:
		print "Incorrect."
		return False

# 5. Hoola-Loop

# Let's use the functions we just wrote to generate a full-blown quiz.
# This introduces the idea of a function parameter, looping, and incrementing
# an int.

def do_quiz(lim):
	current_round = 0
	num_correct = 0

	say_hello_back()
	say_something_smart()

	print "I challenge you to an arithmetic duel!"

	while (current_round < lim):
		was_correct = quiz_me()

		if (was_correct):
			num_correct += 1

		current_round += 1

	print "You score a %d/%d." % (num_correct, lim)

# 6. FizzBuzz Lightyear

# This is a basic implementation of the FizzBuzz puzzle. Introduces the
# range() function along with the notion of a for-each loop. For now, just
# present it as a normal for-loop. White lie.

def fizzbuzz():
	for current_number in range(1, 101):
		if current_number % 15 == 0:
			print "FizzBuzz"
		elif current_number % 3 == 0:
			print "Fizz"
		elif current_number % 5 == 0:
			print "Buzz"
		else:
			print current_number

# 7. Listify FizzBuzz

# Lists are super powerful in Python, and you can manipulate them a hundred different ways.
# That being said, for now we should just stick to basic adding, indexing, etc. This focuses on
# creating an empty list and adding to the end.

def listify_fizzbuzz():
	my_list = []

	for current_number in range(1, 101):
		if current_number % 15 == 0:
			my_list.append("FizzBuzz")
		elif current_number % 3 == 0:
			my_list.append("Fizz")
		elif current_number % 5 == 0:
			my_list.append("Buzz")
		else:
			my_list.append(current_number)

	return my_list

# 8. FizzQuery

# So I know I'm beating this FizzBuzz thing to death, and next time we'll be done, but we need
# a little more practice with lists. So now let's focus on indexing into lists. If you didn't address
# this in the earlier exercises, you might want to discuss casting. Or you can keep putting it off, either one.
# Please note that this will crash if they provide something that is not a number, or if they go out of bounds.
# Try-catch is outside the scope of this tutorial.

def fizz_query():
	fizz_list = listify_fizzbuzz()

	print "Enter any number between 1 and 100 to get the fizzbuzz value. If you want to quit, type \"quit\"."

	while (True):
		query = raw_input('>> ')
		if (query == "quit"):
			break
		else:
			#notice the - 1, talk about 0-based indexing
			print fizz_list[int(query) - 1]

# 9. Prime Sieve

# This is quite a leap in difficulty, but its a fantastic example which combines a lot of the concepts
# we've discussed so far. Looping, lists, modulo, if-statements. Visit: http://en.wikipedia.org/wiki/Sieve_of_Eratosthenes
# for a description of the algorithm.

def prime_sieve(lim):
	is_prime = lim*[True]

	current_number = 2

	while (current_number < lim):
		multiply_by = 2
		current_multiple = current_number * multiply_by
		while (current_multiple < lim):
			is_prime[current_multiple] = False
			multiply_by += 1
			current_multiple = current_number * multiply_by

		current_number += 1
		while (current_number < lim and not is_prime[current_number]):
			current_number += 1

	# Here's the kick ass way to go from boolean list -> primes
	#return [i + 2 for i, elem in enumerate(is_prime[2:]) if elem]

	return_list = []

	for num in range(len(is_prime)):
		if (num is not 0 and num is not 1 and is_prime[num]):
			return_list.append(num)

	return return_list

# 10. Recursion and the turtle package

# This is some serious extra-credit. It introduces the concepts of recursion, and uses a standard library package
# called turtle which makes creating simple animations very very easy. This was stolen shamelessly from: 
# http://interactivepython.org/runestone/static/pythonds/Recursion/graphical.html

def tree(branchLen, current_turtle):
	if branchLen > 5:
		current_turtle.forward(branchLen)
		current_turtle.right(20)
		tree(branchLen - 15, current_turtle)
		current_turtle.left(40)
		tree(branchLen - 15, current_turtle)
		current_turtle.right(20)
		current_turtle.backward(branchLen)

def animate_tree():
	my_turtle = turtle.Turtle()
	myWin = turtle.Screen()
	my_turtle.left(90)
	my_turtle.up()
	my_turtle.backward(100)
	my_turtle.down()
	my_turtle.color("green")
	#Change the first argument to "tree" in order to make the tree more/less awesome -- hint: 100 is pretty awesome
	tree(100, my_turtle)
	myWin.exitonclick()

# THE END!

# This is all the resources I'm going to include in the "standard beginners guide".
# That being said, I have tons more resources, both in the scope of this guide
# as well as beyond the scope of any of this (think packet creation and 2d games)

# print_hello_world()
# say_hello_back()
# say_something_smart()
# quiz_me()
# do_quiz(5)
# fizzbuzz()
# print listify_fizzbuzz()
# fizz_query()
# print prime_sieve(50)
# animate_tree()