Python Map() Function

Python map

Map Function in Python

In this tutorial, we will learn about the Python map() function with the help of examples.

The map() function executes a specified function for each item in an iterable and returns an iterators.

Syntax

	map(function, iterables)

Parameter

function (Required) : The function to execute for each item

iterable (Required): An iterable like sets, lists, tuples, etc

Returns

The map() function is going to apply the given function on all the items inside the iterator and return an iterable map object,example tuple, a list, etc.
The map function, allows us to apply the same operation to each element and return a new list of elements receiving the modified elements from this operation.

Imagine that we have a list of names.

	names = ['RadCliffe', 'Craig', 'Dae Kim', 'Gilles', 'Sharman']

Now we can iterate through the names one by one, add the first name “Daniel”.

	def addDaniel(name):
    return "Daniel " + name

	print(map(addDaniel, names))
# <map object at 0x7f1e182ec1f0>

The map function returns a map object. So, in order to get our desired list back, we need to coerce the map object to a list.

	print(list(map(addDaniel, names)))

	[
 'Daniel RadCliffe',
 'Daniel Craig',
 'Daniel Dae Kim',
 'Daniel Gilles',
 'Daniel Sharman'
]

So the map function goes through each element and executes the altering function on the current element.
Then the return value of the altering function is added as an element to the new list.

	def add(n):
    return n + n

numbers = (9, 5, 7, 3)
result = map(add, numbers)
print(list(result))

# [18, 10, 14, 6]

	def myfunc(n):
  return len(n)

names = ['RadCliffe', 'Craig', 'Dae Kim', 'Gilles', 'Sharman']

print(list(map(myfunc, names)))

# [9, 5, 7, 6, 7]