Can you explain what the built-in map function in Python does and how it is used?

The built-in map function in Python is used to apply a given function to each element of an iterable object (such as a list) sequentially and returns an iterator with the results.

Example of usage:

numbers = [1, 2, 3, 4]

# Function to square a number
def square(x):
    return x * x

squared_numbers = map(square, numbers)

print(list(squared_numbers))  # Outputs: [1, 4, 9, 16]

This is convenient for transforming data without explicit loops. It is also often used with lambda functions:

squared_numbers = map(lambda x: x*x, numbers)

map returns an iterator, so to get a list, you need to wrap the result in list().