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How to use the "map" function in Python?

In Python, the map() function is a built-in function used to apply a specified function to each element of an iterable. It returns an iterator that yields the results of applying the function to each element.

The general syntax of the map() function is as follows:

map(function, iterable)
  • function: The function to be applied to each element of the iterable. It can be a built-in function, a user-defined function, or a lambda function.
  • iterable: The iterable (e.g., list, tuple, string) containing the elements on which the function will be applied.

Here's an example to demonstrate the usage of the map() function:

def square(x):
    return x ** 2

my_list = [1, 2, 3, 4, 5]
mapped_iterator = map(square, my_list)

# Using a for loop to iterate over the mapped_iterator
for result in mapped_iterator:
    print(result)

# Output:
# 1
# 4
# 9
# 16
# 25

In this example, the map() function applies the square() function to each element in my_list. The resulting iterator, mapped_iterator, yields the squared values of the elements when iterated over.

The map() function can also be used with lambda functions, which are anonymous functions defined inline. Here's an example using a lambda function:

my_list = [1, 2, 3, 4, 5]
mapped_iterator = map(lambda x: x ** 2, my_list)

# Using a list comprehension to collect the results of the mapped_iterator
squared_values = [result for result in mapped_iterator]
print(squared_values)

# Output: [1, 4, 9, 16, 25]

In this example, the map() function applies the lambda function lambda x: x ** 2 to each element in my_list. The list comprehension [result for result in mapped_iterator] collects the squared values from the mapped_iterator and stores them in the squared_values list.

The map() function is useful when you want to apply a specific operation or transformation to each element of an iterable and collect the results. It provides a concise and efficient way to perform element-wise computations on an iterable without the need for explicit loops.

It's important to note that the map() function returns an iterator, which means it only produces results on-the-fly as you iterate over it. If you need to store the results in a list or another data structure, you can use a list comprehension or the list() function to convert the iterator into a list.

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