In the previous article, we have discussed Python enumerate() Function with Examples

**filter() Function in Python:**

The filter() function returns an iterator in which the items are filtered through a function to determine whether or not the item is accepted.

**Syntax:**

filter(function, iterable)

**Parameter Values:**

**function:** It is a function that will be executed for each item in the iterable.

**iterable:** The iterable that will be filtered.

**Return Value:**

The iterator is returned by the filter() function.

**Examples:**

**Example1:**

**Input:**

Given List = [3, 10, 12, 13, 20, 7, 1, 16]

**Output:**

The Even numbers in a given list : 10 12 20 16

**Example2:**

**Input:**

Given List = [4, 6, 7, 9, 10, 12, 11]

**Output:**

The Even numbers in a given list : 4 6 10 12

## filter() Function with Examples in Python

### Method #1: Using Built-in Functions (Static Input)

**Approach:**

- Give the list as static input and store it in a variable.
- Create a function say Even_numbers which accepts a number as an argument and returns true if the argument is an even number else it returns false.
- Check if the given number is even using the if conditional statement.
- If it is true, then return True.
- Else return False.
- Pass the above Function(Even_numbers),Â given list as arguments to the filter function that returns an iterator in which the items are filtered through a function to determine whether or not the item is accepted.
- Store it in another variable.
- Loop in the above result using the for loop.
- Print the iterator value of the for loop.
- The Exit of the Program.

**Below is the implementation:**

# Give the list as static input and store it in a variable. gvn_lst = [3, 10, 12, 13, 20, 7, 1, 16] # Create a function say Even_numbers which accepts a number as an argument and returns # true if the argument is even number else it returns false. def Even_numbers(numb): # Check if the given number is even using the if conditional statement. if numb % 2 == 0: # If it is true, then return True. return True # Else return False. else: return False # Pass the above Function(Even_numbers), # given list as arguments to the filter function that # returns an iterator in which the items are filtered # through a function to determine whether or not the item is accepted. # Store it in another variable. evn_numbrs = filter(Even_numbers, gvn_lst) print("The Even numbers in a given list :") # Loop in the above result using the for loop. for n in evn_numbrs: # Print the iterator value of the for loop. print(n)

**Output:**

The Even numbers in a given list : 10 12 20 16

##### Using the Lambda Function Within a filter ()

gvn_lst = [1, 2, 3, 4, 5, 6, 7, 8, 9] # The lambda function returns True for odd numbers oddnumbrs_itrtor = filter(lambda n: (n % 2 != 0), gvn_lst) # converting to list odd_numbrs = list(oddnumbrs_itrtor) print("The Odd numbers in a given list:") print(odd_numbrs)

**Output:**

The Odd numbers in a given list: [1, 3, 5, 7, 9]

Inside the filter, we have directly passed a lambda function ().

For Odd numbers, our lambda function returns True. As a result, the filter() function returns an iterator that only contains Odd numbers.

### Method #2: Using Built-in Functions (User Input)

**Approach:**

- Give the list as user input using map(),list(),input(),int() functions and store it in a variable.
- Create a function say Even_numbers which accepts a number as an argument and returns true if the argument is an even number else it returns false.
- Check if the given number is even using the if conditional statement.
- If it is true, then return True.
- Else return False.
- Pass the above Function(Even_numbers),Â given list as arguments to the filter function that returns an iterator in which the items are filtered through a function to determine whether or not the item is accepted.
- Store it in another variable.
- Loop in the above result using the for loop.
- Print the iterator value of the for loop.
- The Exit of the Program.

**Below is the implementation:**

# Give the list as user input using list(),int(),split() and map() functions # and store it in a variable. gvn_lst = list(map(int, input( 'Enter some random List Elements separated by spaces = ').split())) # Create a function say Even_numbers which accepts a number as an argument and returns # true if the argument is even number else it returns false. def Even_numbers(numb): # Check if the given number is even using the if conditional statement. if numb % 2 == 0: # If it is true, then return True. return True # Else return False. else: return False # Pass the above Function(Even_numbers), # given list as arguments to the filter function that # returns an iterator in which the items are filtered # through a function to determine whether or not the item is accepted. # Store it in another variable. evn_numbrs = filter(Even_numbers, gvn_lst) print("The Even numbers in a given list :") # Loop in the above result using the for loop. for n in evn_numbrs: # Print the iterator value of the for loop. print(n)

**Output:**

Enter some random List Elements separated by spaces = 4 6 7 9 10 12 11 The Even numbers in a given list : 4 6 10 12

Fed up with searching various pages for the list of Python Built in Functions? Look at the tutorial linked here and explore all coding samples of built-in functions of python.