Regular expressions

Now we will begin some of the interesting concepts of preprocessing, which are the most useful. We will look at some of the advanced levels of regular expression.

For those who are new to regular expression, I want to explain the basic concept of regular expression (regex).

Regular expression is helpful to find or find-replace specific patterns from a sequence of characters. There is particular syntax which you need to follow when you are making regex.

There are many online tools available which can give you the facility to develop and test your regex. One of my favorite online regex development tool links is given here: https://regex101.com/

You can also refer to the Python regex library documentation at: https://docs.python.org/2/library/re.html