Introduction Text preprocessing is one of the most important tasks in Natural Language Processing (NLP). For instance, you may want to remove all punctuation marks from text documents before they can be used for text classification. Similarly, you may want to extract numbers from a text string. Writing manual scripts for such preprocessing tasks requires a lot of effort and is prone to errors. Keeping in view the importance of these preprocessing tasks, the Regular Expressions (aka Regex) have been […]

In Python, strings are sequences of characters, which are effectively stored in memory as an object. Each object can be identified using the id() method, as you can see below. Python tries to re-use objects in memory that have the same value, which also makes comparing objects very fast in Python: $ python Python 2.7.9 (default, Jun 29 2016, 13:08:31) [GCC 4.9.2] on linux2 Type “help”, “copyright”, “credits” or “license” for more information. >>> a = “abc” >>> b = […]