filter() function in python by R4R Team

- filter() is a python function which filters the given sequence with the help of a function that tests each element in the sequence to be true or not.

Syntax-

filter(function,sequence)

-It works on the return value by the function, if function return True then filter consider that element otherwise discard.

Example-

we have a function which return True on even number false on odd number
list is [1,2,3,4]
then
filter(function,l) will return [2,4]


program-

l=[1,2,3,4,"one",'two',1.2000]

def func(n):
if type(n)==int:
return True
return False

print("list is",l)
a=filter(func,l)
print("List after filtering")
print(list(a))

def geteven(n):
if n%2==0:
return True
return False

a=filter(geteven,[1,2,3,4])
print("After even filteration, list become")
print(list(a))

output-

list is [1, 2, 3, 4, 'one', 'two', 1.2]
List after filtering
[1, 2, 3, 4]
After even filteration, list become
[2, 4]

-In this program, we have a list [1, 2, 3, 4, 'one', 'two', 1.2] , then firstly we filter all integer value by filter(func,l) func() function return True on integer value, then we have a list [1,2,3,4] then we filter all even element from the list by filter(geteven,l), where geteven return True on even values.