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Python Python Collections (2016, retired 2019) Sets Set Math

Ines Fazlić
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Ines Fazlić
Python Web Development Techdegree Student 9,569 Points
Posted by Ines Fazlić
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Ines Fazlić
Python Web Development Techdegree Student 9,569 Points

set math, don't understand what's wrong with my code

so this is the question: Let's write some functions to explore set math a bit more. We're going to be using this COURSES dict in all of the examples. Don't change it, though!

So, first, write a function named covers that accepts a single parameter, a set of topics. Have the function return a list of courses from COURSES where the supplied set and the course's value (also a set) overlap.

For example, covers({"Python"}) would return ["Python Basics"].

Can please anyone tell me what's wrong with my code? I don't get it..

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(set):
    list: []
    for key, value in COURSES.items():
        if set.intersection(value):
            list.append(key)
    return list

1 Answer

Chris Howell
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Chris Howell
Python Web Development Techdegree Graduate 49,610 Points
Chris Howell
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Chris Howell
Python Web Development Techdegree Graduate 49,610 Points

Hey Ines Fazlić

So it looks like you already figured it out, but I am going to elaborate a little more just in case anyone finds your post and runs into the same problem that way your post can have an answer on it. :-)

: in Python are generally the indicator for a block of code you are about to begin.

Blocks of code can be:

  • Conditional statements like if or else
  • Loops like for or while
  • Functions definitions like def
  • Class definitions like class

These all have a : proceeding them at the end of the line so that Python knows the indented lines beneath them belong inside that block.

Also just a side note about your code below:

def covers(set):
    list: [] # the : here is the problem 
    for key, value in COURSES.items():
        if set.intersection(value):
            list.append(key)
    return list

Be careful using variable names that are also built-in function/class names or keywords in Python.

Here is link to listing of some Python built-ins

If you set a variable name to the same name as anyone of those, you can overwrite the meaning and then wont be able to use it later how you wanted to. So like below you are passing in set into your def covers(set). This may change the way set() normally behaves especially if you pass in something that isnt a set you will change the built-in to something else entirely inside that function. If that makes sense.