lab.md

Python Programming

Unit 2 Lab: Control Flow

Overview

Welcome to the second unit lab! Remember, our goal is that at the end of the fifth lab, you're going to have an app that searches for movies or prints out the Rotten Tomatoes rating for any movie a user enters. Right now, you have a variable to hold a movie title, a variable to hold a movie's rating, and a print statement to show the user. Next, let's set up the functions and control flow to print out the values of our variables.

Deliverables

You're going to continue building this locally from the last lab. You'll write all of your code in the same movie_app.py file. Run the file from the command line to check your work. Reminder: On your laptop, you can run the file from your command line with the following command:

python movie_app.py

Hint: Make sure you are printing something out with the print statement! Otherwise, you won't see any output from running your program!

Requirements:

By the end of this, you will have edited your existing movie_app.py. At the top, you will have a variable called search_or_ratings. Your app will always print : The movie Back to the Future has a great rating! The movie Blade has a great rating! The movie Spirited Away has a great rating! Additionally:

• If search_or_ratings is equal to 1, your app will then print

  Back to the Future
  Blade
  Spirited Away
  

• If search_or_ratings is equal to 2, your app will then print 8.
• If search_or_ratings is equal to 3, your app will then print The rating for Back to the Future is 8.

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Directions

You'll augment the code you wrote for the Unit 1 lab, so leave your two variable declarations at the top of your program and don't delete the print statement!

1. Our program's going to get pretty complex. Let's have a definite starting point. At the bottom of your program, create one main function. From here, we'll call everything else.
2. In programming, if you have a main function, you can set it to automatically run when you start the program. In Python, there's a section of code that does this for us. At the very bottom of your file, put this code:

if __name__ == "__main__":
    main()

1. Now, let's get started! When a user searches for a movie, your program is going to print a whole list of movie titles. But what if we only need to print one title? Create a function called print_movie_title that prints out movie_title.
   1. In main, call print_movie_title.
   2. Try running your program. Do both your print statements show up? We won't keep reminding you, but throughout this lab, run your program every few steps to be sure it's doing what it's supposed to.
2. Let's do the same for the movie rating. Create a function called print_movie_rating that prints out movie_rating. In main, below your call for print_movie_title, call print_movie_rating.
3. What if a user wants to print the whole sentence? Create a function called print_single_movie_rating and move your print sentence from Lab #1 into it. Then, call print_single_movie_rating from main. Your print statement should read something like:

   print('The rating for ' + movie_title + ' is ' + movie_rating + '.')

4. Right now, your main function has three print statements in a row. What if a user doesn't want to print all three? Let's give the user a choice. At the very top of your file, by movie_title and movie_rating, create a variable called search_or_ratings. For now, set it to 1.
   1. In main, let's create an if statement and move our function calls into it. You can then test this out by setting search_or_ratings to different values.
      1. If search_or_ratings is 1, call print_movie_title.
      2. Otherwise, if search_or_ratings is 2, call print_movie_rating.
      3. Otherwise, call print_single_movie_rating.
5. Later, we'll have many movies, so for now, let's temporarily hard code a list to use in our program. At the top of your main function, create a list called default_movie_list and set it to ["Back to the Future", "Blade", "Spirited Away"] (or some other movies you like!).
   1. Let's set a way to print these out. Create a function called print_all_ratings that takes in a parameter movie_list. In it, loop through each movie in movie_list and print "The movie", movie, "has a great rating!" Then, in your main function, call print_all_ratings and pass it default_movie_list. Put this above your if block; it should happen no matter what.
6. Later, a user can search for a movie and see a whole list of matching titles. For now, let's just make the function with our default list. Create a function called list_search_results that takes a parameter movie_titles. In the function, loop through the movie_titles list and print each title out with four spaces ( ) in front of it (just so it looks a little nicer).
   1. Let's think about our new list_search_results function. Right now, in main, if search_or_ratings is set to 1, we call print_movie_title. However, that's when a user is going to want a list of movie titles, not just one movie, right? Change that if statement: if search_or_ratings is set to 1, call list_search_results with the argument default_movie_list instead.
      • Even though we deleted the call to print_movie_title, don't delete the function! We'll use it later, when we only need one movie title. You're done! Test it out to be sure you match the requirements above. Great job.