import re
with open('file.txt', 'r') as f:
    text = f.read()
pattern = r"mypattern"

# Get the first match
match = re.search(pattern, text)

# Get all matches
matches = re.findall(pattern, text)

# Replace any matches with "replacement"
text_replaced = re.sub(pattern, "replacement", text)

# Print the match
print(match)

# Print any captured groups
print(match.groups())

# Write the replacement text back to the file
with open('file.txt', 'w') as f:
    f.write(text_replaced)