Python filter is a very powerful and versatile programming language. One of the many features that make Python so great is the syntax for filtering data sets.This function is a built-in Python language construct that takes in a list of items and filters out those which don’t match a given criterion.
For example, let’s say you have a list of numbers 1,2,3, and 4. You can then pass this list into the filter function with an argument of 2, so it will return only those numbers which are even. This is useful when filtering data such as lists or strings for specific values.
In this blog, we will be going over how to use a Python filter function. Filters are used in list comprehensions, and the type of filter is dependent on what you want to do with it. You can make a copy of the list or remove items from the list and sort them!
Table of Contents
Python Filter Function
The Filter function can process an iterable and extract those items that satisfy a given condition. The function returns a list of items from the iterable for which the specified function evaluates True.
Python Filter Function Syntax
The syntax is:
filter(function/ none, iterable) If the optional function argument is missing, the identity function is assumed.
Example Code
This python example shows how to use python’s built-in function filter().
def vowels_filter(Alphabet):
vowels = ['a', 'e', 'i', 'o', 'u']
return True if Alphabet in vowels else False
Alphabets = ['a', 'b', 'd', 'e', 'f', 'j', 'k', 'm', 'o', 't', 'u', 'y']
vowels_extracted = filter(vowels_filter, Alphabets)
vowels = tuple(vowels_extracted)
print(vowels) Output
Python Filter Lambda
The function is mainly used with a lambda function to extract the list, set, or tuple.
Example Code
MyList = [0, 1, 2, 3, 4, 15, 16, 17, 20, 25, 30]
result = filter(lambda x: x % 2 != 0, MyList)
print(list(result)) Output
What are the advantages of Python Filter( )?
It is very useful in
- Python web scraping,
- Python for data mining, and
- Python programming utilities.
Conclusion
If you’ve been using Python for a while, you may have seen the filter() function before. It’s one of those functions that can be used to perform filtering operations on iterables, and it comes in handy more often than not. I hope the article helped you.
