remove from 1st upper case alphabetical character to end of string and and special character

I have a small exercise that required me to remove all special character and the 1st upper case alphabetical character to end of string except dots [.] and hyphens [-] .I tried the solution here https://www.geeksforgeeks.org/remove-uppercase-lowercase-special-numeric-and-non-numeric-characters-from-a-string/
The string below example is one of the example

import re

def removingUpperCaseCharacters(str):
    regex = "[A-Z]"
    return (re.sub(regex, "", str))
def removingSpecialCharacters(str):
 
    # Create a regular expression
    regex = "[^.A-Za-z0-9]"
 
    # Replace every matched pattern
    # with the target string using
    # sub() method
    return (re.sub(regex, "", str))
str = "teachert.memeCon-Leng:"
print("After removing uppercase characters:",
       removingUpperCaseCharacters(str))
print("After removing special characters:",
       removingSpecialCharacters(str))

The output is

After removing uppercase characters: teachert.memeontent-ength:
After removing special characters: teachert.memeContentLength

The ouput I want is

teachert.meme

>Solution :

You could replace one of your functions as follows:

def removingUpperCaseCharacters(str):
    i = 0
    while i < len(str) and (ord('A') > ord(str[i]) or ord('Z') < ord(str[i])):
        i += 1
    return str[:i]