Validating Email Addresses With a Filter Solution
You are given an integer followed by email addresses. Your task is to print a list containing only valid email addresses in lexicographical order.
Valid email addresses must follow these rules:
- It must have the [email protected] 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 .
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 to (both included).
>> l = list(range(10)) >> l = list(map(lambda x:x*x, l))
Now, you only require those elements that are greater than but less than .
>> l = list(filter(lambda x: x > 10 and x < 80, l))
Easy, isn't it?
The first line of input is the integer , the number of email addresses.
lines follow, each containing a string.
Each line is a non-empty string.
Output a list containing the valid email addresses in lexicographical order. If the list is empty, just output an empty list, .
3 [email protected] [email protected] [email protected]
['[email protected]', '[email protected]', '[email protected]']
Solution in Python
def fun(s): try: user, www = s.split("@") web, ext = www.split(".") if not user or not web or not ext: return False return not any([user != "".join(filter(lambda x: x.isalnum() or x in ["_", "-"], user)), web != "".join(filter(lambda x: x.isalnum(), web)) , len(ext)>3]) except: return False def filter_mail(emails): return list(filter(fun, emails)) if __name__ == '__main__': n = int(input()) emails =  for _ in range(n): emails.append(input()) filtered_emails = filter_mail(emails) filtered_emails.sort() print(filtered_emails)