# Validating Email Adresses With a Filter python

### Problem Statement :

```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.
The website name can only have letters and digits.
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?

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.

Output Format

Output a list containing the valid email addresses in lexicographical order. If the list is empty, just output an empty list, [].```

### Solution :

```                            ```Solution in C :

import sys, re
n = int(input())
a = [input() for i in range(n)]
print(sorted([s.strip() for s in a if re.match(r'^[a-zA-Z0-9_-]+@[a-zA-Z0-9]+\.[a-zA-Z0-9]{1,3}\$', s)]))```
```

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