• re.VERBOSE for writing regular expression that seems better, readable, and enable to split logic part from pattern visually and add comment.
• Space in ignored pattern, unless when in the character class or when it preceded by backslah that cannot be deleted or inside the token such as *?, (?: or (?P.
  • Meaning of some symbol
• When a line consists of # that does not exist in character class and it is not preceded by backslash, all character from # very left to end of line will be ignored.

# Without Using VERBOSE
regex_email = re.compile(r'^([a-z0-0_\\\\.-]+)\\.([a-z\\.]{2,6})$',
       re.IGNORECASE) 

# Using VERBOSE
regex_email = re.compile(r"""
      ^([a-z0-9_\\.-]+)            # local part
       @             # single @ sign
       ([0-9a-z\\.-]+)       # Domain name
       \\.            # single Dot .
       ([a-z](2,6))$        # Top level Domaim
       """,re.VERBOSE | re.IGNORECASE)

• Note

It will be forwarded as argument into re.compile() which re.compile(Regular Expression, re.VERBOSE) . re.compile() will return RegexObject which later will be matched with the string that is given.

Let’s we consider example where the user is requested to enter their email ID and we have to validate it using RegEx. The email format is attached below:

• Personal details/local part like john123
• Single @
• Domain Name like gmail/yahoo etc
• Single Dot(.)
• Top Level Domain like.com/org/.net

Input: [email protected]

Output: Valid

Input: [email protected]@

Output: Invalid invalid because there is @ after top-level domain name

Implementation