Manish Barnwal

...just another human

Types of data in recommender systems

There are two ways in which we can collect data for building recommender systems — explicit and implicit. In this post, we will talk about both types of data, their characteristics and the challenges with them.

Explicit feedback datasets

The dictionary meaning of explicit is to state clearly and in detail ...

Handling errors with try-catch in Python

In the previous post I discuss about how to convert a string to date format in Python. I was working on similar idea today. I had a column of object type which was string of dates. The column name is 'signed_up_at' and I wanted to convert it to date format ...

Working with dates in Python

from datetime import datetime

To convert a string to date:

`datetime.strptime('string', 'format_of_the_string')``

d1 = datetime.strptime('2017-02-02', '%Y-%m-%d')

`d2 = datetime.strptime('2018-06-17', '%Y-%m-%d')``

Find the number of days between two dates `delta = d2 - d1 delta.days ``

Difference between today and some date today = ...

git and github for data scientists

It has been close to a year since I shifted to a start-up which incidentally got acquired after a month of my joining. Before this I used to work at WalmartLabs where we always wanted to use a version control system like git but it never took off properly. Now ...

Creating a virtual environment in Python

I was trying to get a virtual environment set up on Python 3 using mkvirtualenv but somehow the virtual environment was getting created on Python 2.7 (my system python).

If you already know about virtual environments and why they are useful, you may skip the next two paragraphs. I ...

Common docker commands

Photo of docker

I recently got to know about dockers. And I love it. For those who don't know what dockers are. Here it is. Dockers help in software ...

Tutorial on dplyr- a package for data manipulation in R

R is the most used tool in data science. It has no dearth of packages for specific use cases. There are three packages that I feel can get your most of the work done - ggplot2, dplyr, data.table.

  • ggplot2- Used for visualization. Also known as grammar of graphics. This package ...

The essence of machine learning is function estimation

Machine learning is cool. There is no denying in that. In this post we will try to make it a little uncool, well it will still be cool but you may start looking at it differently. Machine learning is not a black box. It is intuitive and this post is ...

Time series and forecasting using R

Time series forecasting is a skill that few people claim to know. Machine learning is cool. And there are a lot of people interested in becoming a machine learning expert. But forecasting is something that is a little domain specific.

Retailers like Walmart, Target use forecasting systems and tools to ...