Practical Programming, Third Edition

Exercises

Here are some exercises for you to try on your own. Solutions are available at http://pragprog.com/titles/gwpy3/practical-programming.

Two of Python’s built-in functions are min and max. In the Python shell, execute the following function calls:
1. min(2, 3, 4)
2. max(2, -3, 4, 7, -5)
3. max(2, -3, min(4, 7), -5)
For the following function calls, in what order are the subexpressions evaluated?
1. min(max(3, 4), abs(-5))
2. abs(min(4, 6, max(2, 8)))
3. round(max(5.572, 3.258), abs(-2))
Following the function design recipe, define a function that has one parameter, a number, and returns that number tripled.
Following the function design recipe, define a function that has two parameters, both of which are numbers, and returns the absolute value of the difference of the two. Hint: Call built-in function abs.
Following the function design recipe, define a function that has one parameter, a distance in kilometers, and returns the distance in miles. (There are 1.6 kilometers per mile.)
Following the function design recipe, define a function that has three parameters, grades between 0 and 100 inclusive, and returns the average of those grades.
Following the function design recipe, define a function that has four parameters, all of them grades between 0 and 100 inclusive, and returns the average of the best 3 of those grades. Hint: Call the function that you defined in the previous exercise.

Complete the examples in the docstring and then write the body of the following function:

	def weeks_elapsed(day1, day2):
	""" (int, int) -> int

	day1 and day2 are days in the same year. Return the number of full weeks
	that have elapsed between the two days.

	>>> weeks_elapsed(3, 20)
	2
	>>> weeks_elapsed(20, 3)
	2
	>>> weeks_elapsed(8, 5)

	>>> weeks_elapsed(40, 61)

	"""

Consider this code:

In the following table, fill in the Example column by writing square, num, square(3), and 3 next to the appropriate description.