Python: Difference between filter(function, sequence) and map(function, sequence)

Question

I\'m reading through the Python documentation to really get in depth with the Python language and came across the filter and map functions. I have used filter before, but never

Answer 1

map and filter function in python is pretty different because they perform very differently. Let's have a quick example to differentiate them.

map function

Let's define a function which will take a string argument and check whether it presents in vowel letter sequences.

def lit(word):
    return word in 'aeiou'

Now let's create a map function for this and pass some random string.

for item in map(lit,['a','b','e']):
    print(item)

And yes it's equivalent to following

lit('a') , lit('b') , lit('e')

simply it will print

True
False
True 

filter function

Now let's create a filter function for this and pass some random string.

for item in filter(lit,['a','b','e']):
    print(item)

filter as the name implies, filters the original iterable and retents the items that return True for the function provided to the filter function.

Simply it will print

a
e

Fork it here for future reference, if you find this useful.