Step by Step solution about How to resolve the algorithm Nested function step by step in the Python programming language

This Python code defines a function called makeList that takes a separator as input and returns a string containing a list of items with the provided separator inserted between each item. Inside the makeList function, a nested function called makeItem is defined and returned. The makeItem function takes an item as input and returns a string formatted with the item's position in the list, the provided separator, and the item itself, followed by a newline character.

To achieve this, makeItem uses a nonlocal variable named counter that is shared with the outer makeList function. The counter variable is used to keep track of the position of each item in the list. Each time makeItem is called, it increments the counter and formats a string using the current position, the separator, and the provided item.

The makeList function calls makeItem three times to create a list of three items: "first," "second," and "third." The results of these calls are then concatenated into a single string, which is returned by the makeList function.

Finally, the print statement outside the makeList function calls makeList with a separator of ". " and prints the returned string, which will be a numbered list of the three items:

1. first
2. second
3. third

def makeList(separator):
    counter = 1

    def makeItem(item):
        nonlocal counter
        result = str(counter) + separator + item + "\n"
        counter += 1
        return result

    return makeItem("first") + makeItem("second") + makeItem("third")

print(makeList(". "))