Unsupervised Learning -- A Complete Overview

It is a Machine Learning technique in which instead of learning from training dataset(as in supervised learning), here model itself find hidden patterns and insights from the data. It create groups based on some similarity even without knowing what each group represent. In this article i will not explain each and every thing in brief, i will only give an short overview about the different types of unsupervised learning. Most of time peoples ask me what is Unsupervised Learning and how many types of it, i googled it but didn't get an perfect answers of this question this is only my motto of writing this article. Example: Suppose we have group of students belongs to different university's and we have to group them based on some feature, now we give this responsibility to unsupervised algorithms.