explanation of how the code works

Question

I have got this code from a previous student. I am trying to reverse engineer it but finding it difficult. Could someone please break this down for how this works from line 3 downwards

sets.py

COURSES = {
    "Python Basics": {"Python", "functions", "variables",
                      "booleans", "integers", "floats",
                      "arrays", "strings", "exceptions",
                      "conditions", "input", "loops"},
    "Java Basics": {"Java", "strings", "variables",
                    "input", "exceptions", "integers",
                    "booleans", "loops"},
    "PHP Basics": {"PHP", "variables", "conditions",
                   "integers", "floats", "strings",
                   "booleans", "HTML"},
    "Ruby Basics": {"Ruby", "strings", "floats",
                    "integers", "conditions",
                    "functions", "input"}
}
def covers(x):
    courses_list = []
    for course in COURSES:
        if x.intersection(COURSES[course]):
            courses_list.append(course)
    return courses_list

Answer 1 · 2019-04-06T17:02:02Z

April 6, 2019 5:02pm

Here's a breakdown:

  courses_list = []                     # start with an empty list
  for course in COURSES:                # check each course, one at a time
    if x.intersection(COURSES[course]): # if the set (x) has anything in common with the course 
      courses_list.append(course)       # then add the name of the course to the list
  return courses_list                   # finally return the new list

Note that an intersection is only those items both sets have in common. If it is empty, it will be "falsey" to the "if". But if there is at least one thing in it, it will be "truthy".

Does that clear it up?

Welcome to the Treehouse Community

Looking to learn something new?

Sohail Mirza

Sohail Mirza

explanation of how the code works

1 Answer

Steven Parker

Steven Parker