RanRag has already answered it for your specific question.

However, more generally, what you are doing with

if [[ "$string" =~ ^hello ]]

is a regex match. To do the same in Python, you would do:

import re
if re.match(r'^hello', somestring):
    # do stuff

Obviously, in this case, somestring.startswith('hello') is better.

you can use urllib.parse.urlparse

from urllib.parse import urlparse


url = 'https://www.youtube.com/watch?v=nVNG8jjZN7k'

if urlparse(url).scheme in ("http", "https"):
   ...

More useful methods in the docs https://docs.python.org/3/library/urllib.parse.html#module-urllib.parse

You can pass a tuple to startswiths() (in Python 2.5+) to match any of its elements:

import string
ALPHA = string.ascii_letters
if line.startswith(tuple(ALPHA)):
    pass

Of course, for this simple case, a regex test or the in operator would be more readable.

You can write a function that checks if the string provided starts with a vowel:

def starts_with_vowel(str):
    return str.lower().startswith(("a", "e", "i", "o", "u")) # lower to be more general

variable1 = "open"

# check if it starts with a vowel
if starts_with_vowel(variable1):
    print("correct")

You can also use any(), map() like so:

if any(map(l.startswith, x)):
    pass # Do something

Or alternatively, using a generator expression:

if any(l.startswith(s) for s in x)
    pass # Do something