Learn Functional Programming in Python/

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Map

Map

Learn how to use the function, "map", to transform iterables by applying a function to them.

We'll cover the following...

map function

The map function applies a supplied function to a set of arguments. It returns an iterator to access the results.

map with one parameter

In this example, we will use map with a user-defined function, square, that takes one parameter.

Python 3.8
def square(x): 
    return x*x 
a = [2, 5, 6] 
m = map(square, a)
print(list(m))

The map function applies square to each element in a, returning the squared values via an iterator. On line 7, we convert m to a list and print it.

Lazy evaluation

This is perhaps a good time to revisit the idea of lazy evaluation. All the functions described so far use lazy evaluation. We will illustrate this by ...