## Algorithm

Problem Name: Python - Validating Email Addresses With a Filter

In this HackerRank Functions in PYTHON problem solution,

You are given an integer N followed by N email addresses. Your task is to print a list containing only valid email addresses in lexicographical order.

• It must have the username@websitename.extension format type.
• The username can only contain letters, digits, dashes and underscores [a - z],[A - Z],[0 - 9],[_-].
• The website name can only have letters and digits [a - z],[A - Z],[0 - 9].
• The extension can only contain letters [a - z],[A - Z].
• The maximum length of the extension is 3.

Concept

A filter takes a function returning True or False and applies it to a sequence, returning a list of only those members of the sequence where the function returned True. A Lambda function can be used with filters.

Let's say you have to make a list of the squares of integers from 0 to 9 (both included).

``````>> l = list(range(10))
>> l = list(map(lambda x:x*x, l))
``````

Now, you only require those elements that are greater than 10 but less than 80 .

``````>> l = list(filter(lambda x: x > 10 and x < 80, l))
``````

Easy, isn't it?

Example

Complete the function fun in the editor below.

fun has the following paramters:

• string s: the string to test

Returns

• boolean: whether the string is a valid email or not

Input Format

The first line of input is the integer N ,the number of email addresses.

N lines follow, each containing a string.

Constraints

Each line is a non-empty string.

Sample Input

``````3
lara@hackerrank.com
brian-23@hackerrank.com
britts_54@hackerrank.com
``````

Sample Output

``````['brian-23@hackerrank.com', 'britts_54@hackerrank.com', 'lara@hackerrank.com']
``````

## Code Examples

### #1 Code Example with Python Programming

```Code - Python Programming```

``````
def fun(email):
try:
website, extension = url.split(".")
except ValueError:
return False

if username.replace("-", "").replace("_", "").isalnum() is False:
return False
elif website.isalnum() is False:
return False
elif len(extension) > 3:
return False
else:
return True
``````
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