Regular Expressions

Really just a pattern. REGEX

email = input("What's your email? ").strip()

if "@" in email and "." in email:
	print("Valid")
else:
	print("Invalid")

email = input("What's your email? ").strip()

username, domain = email.split("@")

#if username and "." in domain:
if username and domain.endswhith(".edu"):
	print("Valid")
else:
	print("Invalid")

Regular Expression (RE)

Python Documentation

re.serach

import re

email = input("What's your email? ").strip()

if re.serach("@", email):
	print("Valid")
else:
	print("Invalid")

Validation characters

.   any character except a new line
*   0 or more repetitions
+   1 or more repetitions
?   0 or 1 repetition
{m} m repetitions
{m,n} m-n repetitions

^   matches the start of the string
$   matches the end of the string or just before the newline at the end of the string

[]    set of characters
[^]   complementing the set

\d    decimal digit
\D    not a decimal digit
\s    whitespace characters
\S    not a whitespace character
\w    word character, as well as numbers and the underscore
\W    not a word character

A|B     either A or B
(...)   a group
(?:...) non-capturing version

r can be used to create a raw string

import re

email = input("What's your email? ").strip()

if re.search(r".+@.+\.edu", email):
    print("Valid")
else:
    print("Invalid")

Flags

re.IGNORECASE
re.MULTILINE
re.DOTALL

Format.py

name = input("What's your name? ").strip()
print(f"hello, {name}")

Using re instead of split

import re

name = input("What's your name? ").strip()
if matches := re.search(r"^(.+), *(.+)$", name):
    name = matches.group(2) + " " + matches.group(1)
print(f"hello, {name}")