filter in python
The filter() is a built-in function that allows you to process an iterable (list, tuple etc.) for which a function returns True.
Syntax
filter(function, iterable)
Note: Since
filter()is a built-in function, you don’t have to import anything to be able to use it in your code.
Arguments
function– The first argument tofilter()is a function object, which means that you need to pass a function without calling it with a pair of parentheses.iterable– The second argument, iterable, can hold any Python iterable, such as a list, tuple, or set.
Return Value
Note: You can easily convert iterators to sequences like lists, tuples, strings etc.
filter python
Example 1
Filter out the number less than 20 in given list.
numberList = [11, 22, 33, 14, 15, 16, 20, 4, 5, 1, 43, 55, 66] def getLessThan20Func(numList): if(numList < 20): return True else: return False numbers = filter(getLessThan20Func, numberList) for i in numbers: print(i)
Output
11 14 15 16 4 5 1
Example 2
Lets filter the vowels in given list
letters = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o'] def filterVowels(letter): vowels = ['a', 'e', 'i', 'o', 'u'] return True if letter in vowels else False filtered = filter(filterVowels, letters) vowels = tuple(filtered) print(vowels)
Output
('a', 'e', 'i', 'o')
Example 3
Let’s filter the even numbers from the given list of numbers using the filter function
numberList = [11, 22, 33, 14, 15, 16, 20, 4, 5, 1, 43, 55, 66] def isEven(numList): if(numList %2 == 0): return True else: return False numbers = filter(isEven, numberList) for i in numbers: print(i)
Output
22 14 16 20 4 66