replaces the main function from c

Matches a variable with the following syntax; = example string foo = ...

A simple regex to capture different formats of decimal numbers. Note: the last string "720p" I have skipped it. My regex will not take that last string into account. This is just an exercise from https://regexone.com/problem/matching_decimal_numbers

captures all possible email username/domain formats

positive look behind: it does not consume the first character, so it can be used for the next match flags=re.I is to ignore case sensitive