Advanced Python: Recursion

Name: Advanced Python: Recursion
Author: Jeremy Kurtz

Add to your knowledge of the Turtle function

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Course: On-Demand

(gentle music) In this lesson, we are going to talk about recursion. Now recursion is very difficult to describe but it's quite easy to understand. So we'll spend more time doing than talking. What recursion is, is in our case, it's a function in Python that calls itself to derive an answer. Now, I know that's difficult to understand but if you recall, as a youth, you were probably told never use the word you're defining in the definition of that word. That is exactly what recursion is. So if I have a piece of cheese and two pieces of bread and I put the piece of cheese between the two pieces of bread, if you look at that sandwich from either side of the sandwich, both of them could be the top, both of the pieces of bread could be the bottom. The top with the cheese is a mirror of the bottom and the cheese, that is recursion. In Python it's used a lot in the calculation of different mathematical processes. In our case, we're going to take lesson three and we're going to save it as lesson four. And what we're going to create is we're going to create probably the most popular of the recursive functions and that is dividing the factorial of a number. So the first thing we have to do is we have to create a function. So we define the function and we'll call it factor. And factor is going to take in a variable. In our case, it's going to be an integer. And we are going to define that function by using function in its definition. Now, what we're going to do is we're going to create an if statement to allow this function to call itself. So if num equals one, meaning if someone enters the number one into our program, then it won't do anything because num does not have a factorial. So it will just return itself. Else, it is going to return num times factor num minus one. And there's our function. So now instead of having an input statement or anything like that, we are just going to assign a value to a variable. Out here after the if statement, we're going to create a variable called X and we're going to assign to it, the number five. After we set the variable we can now just write a print statement that calls and prints out the return value of our function. So it's print factor. And then inside of factor, we have X and now we can save it and run it. And the factorial of five is 120. What a factorial is, is any number that is multiplied by every number that precedes it until it reaches one. So in the case of ours, we have five times four times three times two times one. And that is recursion. In our next lesson, we're going to look at an elegant example of recursion. So see you then.

Advanced Provider : Jeremy Kurtz 6 Lessons · 38m in Arabic, German, English, Spanish, French, Portuguese, Chinese

Course Description

In this course, you will master the functions of the common mathematical and programming concept of recursion in Advanced Python. Using this knowledge from the course on the turtle function, you will gain experience in recursion within the turtle function.

What You'll Learn

Use mathematical and programming concepts in Advanced Python
Implement recursion with functions
Apply recursion to factorials
Build recursive solutions using the turtle function across multiple stages
Develop advanced function presentation and recursive descent skills

Key Takeaways

Recursion is a concept common to both mathematics and programming, covered here in Advanced Python.
The course applies recursion within the turtle function to give hands-on experience.
Factorials are used as an example of implementing recursion.
The turtle-based recursion material is taught progressively across five parts.

Frequently Asked Questions

What does this course cover?

It covers recursion as a mathematical and programming concept in Advanced Python, including recursion with factorials and recursion within the turtle function across five parts.

What skills will I gain from this course?

You will gain skills in Advanced Function Presentation, Advanced Mathematics, Programming Concepts, Python (Programming Language), Recursion, and Recursive Descent.

How is the course structured?

It is organized into lessons covering Recursion and Factorials followed by Recursion and the Turtle in five parts.

What will I be able to do after taking this course?

You will be able to use mathematical programming concepts and implement recursion with functions.