Python - Map and Filter

map

The built-in functions map and filter are very useful higher-order functions that operate on lists (or similar objects called iterables). 
The function map takes a function and an iterable as arguments, and returns a new iterable with the function applied to each argument. 
Example:

def add_five(x):
return x + 5

nums = [11, 22, 33, 44, 55]
result = list(map(add_five, nums))
print(result)

Result:>>>
[16, 27, 38, 49, 60]
>>>
We could have achieved the same result more easily by using lambda syntax.

nums = [11, 22, 33, 44, 55]

result = list(map(lambda x: x+5, nums))
print(result)

To convert the result into a list, we used list explicitly.

filter

The function filter filters an iterable by removing items that don't match a predicate (a functionthat returns a Boolean). 
Example:

nums = [11, 22, 33, 44, 55]
res = list(filter(lambda x: x%2==0, nums))
print(res)

Result:>>>
[22, 44]
>>>
Like map, the result has to be explicitly converted to a list if you want to print it.