import re

text = 'Special Agent Upsorn told Special Agent Awesome a secret'
# replace the agent's name with  ***AAAAA***

# find a match
# replace that match with ?????

regex = re.compile(r'Agent [A-Z][a-z]+')
for match_obj in regex.finditer(text):
    print('match object --', match_obj.group())

string = regex.sub('?????', text)
print('replace --', string)


# grouping
# agent_name_regex = re.compile(r"Agent (\w)\w*")
# agent_name_regex = re.compile(r"Agent ([A-Z])[a-z]*")
# agent_name_regex = re.compile(r"Agent ([A-Z])([a-z])[a-z]*")

agent_name_regex = re.compile(r"(Agent )([A-Z])([a-z])[a-z]*")    # make regex into 3 groups and use group 2 in replacement

search_result = agent_name_regex.search(text)    # return the first match object
print(search_result.group(0), '=', search_result.group())
print('groups --', search_result.groups())
if search_result != None:   # index starts from 1
    for i in range(1, len(search_result.groups())+1):
        print('index', i, search_result.group(i))


# sub(pattern_to_replace, original_string)

# for each match object, keep the 1st group, replace the remaining groups
string = agent_name_regex.sub(r"\1?????", text)      # replace with the 1st group followed by ?????
print("1st group:", string)

# for each match object, keep the 2nd group, replace the remaining groups
string = agent_name_regex.sub(r"####\2?????", text)
print("2nd group:", string)