Write a function called remove_all_from_string that takes two strings

Write a function called remove_all_from_string that takes two strings, and returns a copy of the first string with all instances of the second string removed. This time, the second string may be any length, including 0.
Test your function on the strings “bananas” and “na”. Print the result, which should be:
bas
You must use:
A function definition with parameters.
A while loop.
The find method.
The len function.
Slicing and the + operator.
A return statement

The Correct Answer and Explanation is :

Here’s how you can implement the remove_all_from_string function in Python. The function takes two strings: the first string from which you want to remove occurrences of the second string. It uses a while loop, the find method, slicing, and the len function to accomplish this.

def remove_all_from_string(original, to_remove):
    result = ""  # Initialize an empty string to hold the result
    start = 0  # Initialize the starting index for searching

    # Use a while loop to find and remove all occurrences of to_remove
    while True:
        # Find the index of the first occurrence of to_remove in original
        index = original.find(to_remove, start)

        # If no more occurrences are found, break out of the loop
        if index == -1:
            break

        # Append the part of original before the found index to result
        result += original[start:index]

        # Move the starting index past the found occurrence
        start = index + len(to_remove)

    # Append any remaining part of original to result
    result += original[start:]

    return result

# Test the function
result = remove_all_from_string("bananas", "na")
print(result)  # Output: bas

Explanation

1. Function Definition: The function remove_all_from_string is defined with two parameters: original and to_remove. This makes it flexible for any input strings.
2. Initialization: We initialize result as an empty string, which will hold the modified version of the original string. The variable start is set to zero to track our current position in the original string.
3. While Loop: We use a while loop that will continue until we find no more occurrences of to_remove. Inside the loop, the find method is called on original, searching for to_remove starting from the current start index. If the find method returns -1, it means there are no more occurrences, and we break the loop.
4. Slicing and Concatenation: When an occurrence is found, we slice the original string up to the index of the found substring and append it to result. We then update the start index to continue searching beyond the current occurrence.
5. Final Result: After exiting the loop, any remaining portion of original from the start index is appended to result. Finally, the function returns result.
6. Testing: The function is tested with the strings “bananas” and “na”. The expected output is “bas”, which is printed to the console.

This method efficiently removes all instances of the specified substring, demonstrating fundamental programming concepts in Python.