This article shows how you can do Stemming and Lemmatisation on your text using NLTK.
You can read about introduction to NLTK in this article: Introduction to NLP & NLTK

This article shows how you can use the default Stopwords corpus present in Natural Language Toolkit (NLTK).
To use stopwords corpus, you have to download it first using the NLTK downloader. In my previous article on Introduction to NLP & NLTK, I have written about downloading and basic usage example of different NLTK corpus data.

Natural Language Processing (NLP) is about the processing of natural language by computer. It’s about making computer/machine understand about natural language. Natural language means the language that humans speak and understand.
Natural Language Toolkit (NLTK) is a suite of Python libraries for Natural Language Processing (NLP). NLTK contains different text processing libraries for classification, tokenization, stemming, tagging, parsing, etc.

This article deals with implementing Bubble Sort algorithm using Python programming language.
Bubble Sort is a simple sorting algorithm that compares each element in the list with its adjacent element and sort that pair of elements if they are not in order.