Recursive Call

Next, we’ll add the recursive call. Here's where we left off:

def factorial(n):
    """Compute n! where n is an integer >= 0."""
    case n:
        match 0:
            return 1

# Test cases:
0 |> factorial |> print  # 1
3 |> factorial |> print  # 6

We want our next match statement to check if n is an integer and greater than 0.

Add a match statement that checks whether n matches to x is int. This'll check if n is an integer.

The second attribute of n we want to check for is if it’s greater than 0. To do this, add the conditional if x > 0 right after the x is int pattern.

If n matches this pattern, we want to return n times the recursive call to factorial.

Double-click starter code, implement the recursive call, and then run the code to make sure the test cases pass!

Show Solution:

def factorial(n):
                """Compute n! where n is an integer >= 0."""
                case n:
                    match 0:
                        return 1
                    match x is int if x > 0:
                        return x * factorial(x-1)

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