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numbers = [1, 2, 3, 4, 5, 6]

def is_even(number):
    return number % 2 == 0

# filter function
even_numbers = filter(is_even, numbers)
even_list = list(even_numbers)
print(even_list)

print()

def square(number):
    return number * number

# map function
squared_numbers = map(square, numbers)
print(list(squared_numbers))

# Processing Sequences with filter() and map() Functions

The `filter()` and `map()` functions in Python are used to process elements of iterable objects like lists and tuples.

The `filter()` function is used to filter elements that satisfy a given condition, and the `map()` function applies a specified function to each element, creating a new sequence.

<br />

## Using the filter() Function

The `filter()` function generates a new sequence composed of elements for which the given function returns `True`.

The first argument of the filter function is a **callback function**, and the second argument is the **iterable object** (sequence).

```python title="Usage of filter function"
filter(function, iterable)
```

For example, the `filter()` function can be used to filter even numbers from a given list of numbers as shown below.

```python title="Example of using filter() function"
# Callback function to filter even numbers
def is_even(number):
    return number % 2 == 0

# List of numbers
numbers = [1, 2, 3, 4, 5, 6]

# Using filter() function
even_numbers = filter(is_even, numbers)

even_list = list(even_numbers)
print(even_list)
# [2, 4, 6]
```

<br />

## Using the map() Function

The `map()` function takes an iterable object, applies a specified function to each element, and creates a new `map object` containing the results.

It can be used with any iterable object like lists, tuples, or strings, and the new `map object` can be converted into other data types like lists or tuples.

```python title="Usage of map function"
map(function, iterable)
```

This function is commonly used in data transformation tasks, making it useful for processing all elements of an iterable object in bulk.

```python title="Example of using map() function"
# Callback function to square numbers
numbers = [1, 2, 3, 4, 5, 6]

def square(number):
    return number * number

# Using map() function
squared_numbers = map(square, numbers)

print(list(squared_numbers))
# [1, 4, 9, 16, 25, 36]
```

The `filter()` function filters a sequence to create a new sequence with elements that satisfy a condition. It only includes elements for which the given function returns True.

Processing Sequences with filter() and map() Functions

Using the filter() Function

Using the map() Function

What is the purpose of the filter() function in Python?

What is the purpose of the `filter()` function in Python?