Python Programming

Ok, I have provided you with the basics of regular expressions. Hopefully you are able to write your own regular expressions by now!

As a recap, here are the special metacharacters for regular expressions in Python.

• .: Match any characters except a newline.
• ?: Match zero or one repetitions
• *: Match zero or more repetitions
• +: Match one or more repetitions
• [ ]: Match a set of characters
• ( ): Grouping
• |: Or
• {m}: Match exactly m repetitions
• {m,n}: Match m to n repetitions. Omitting n will give you infinity.
• ^: Match the start of a string, or “not” if used inside [ ].
• $: Match the end of a string
• \b: Word boundary marker. Remember to use raw strings r"\b" or escape it "\\b" when using this in Python.
• \: Escape characters. Use this to represent any of the metacharacters above (e.g. "\?" if you want to match a question mark). Escaping is not needed inside square brackets.