regression toward the datascience

Resample timeseries data with custom function


With timeseries data we often require to resample on different intervel to feed in to our analytics model.

Pandas resample have a built-in list of widely used methods. However, if the built-in methods are not sufficient, it is always possible to write a custom function to resample.

This post shows ...

Birthday paradox


Building python visualization of the famous Birthday paradox or Birthday problem.

Birthday problem, is to find the probability of a pair from the given set of randomly chosen people to have same birthday.

Given, we have 365 days (ignoring February 29th). The following chart shows how the probability increases with ...

Adding empty directory within GIT


While maintaining GIT repositories, in some cases, we might be required to add an empty directory as a placeholder to mean something or we wanted all the files in a directory to stay local. However in GIT we can add only files to the repository and not the directory.

I ...

Tornado Error during WebSocket handshake


I was getting following exeption in WebSocket client, when trying to connect Tornado WebSocket server.

WebSocket connection to 'ws://localhost:5678/echo' failed: Error during WebSocket handshake: Unexpected response code: 403

and on the server-side log

WARNING:tornado.access:403 GET /echo (::1) 6.00ms

A simple Echo WebSocket server ...

Binding port 80 to tomcat in Ubuntu


Edit the file /etc/default/tomcat7

change the line




and run the following commands

$ sudo touch /etc/authbind/byport/80
$ sudo chmod 500 /etc/authbind/byport/80
$ sudo chown tomcat7 /etc/authbind/byport/80

Hope this helps.

Building Hadoop source code


The Apache Hadoop is a framework that allows for distributed processing of large data sets across clusters of computers using MapReduce.

The steps listed below is to build and package hadoop from source code. This guide assumes a fresh installation of Ubuntu 14.04 version.

  1. Let's start with installing ...

Pig script to process CSV file with quotes and multiline


While writing Pig script, usually we use PigStorage for loading a CSV file.

Consider a sample CSV file in the following format.

2,Loading successfull,2014-09-25
3,Loading successfull,2014-09-25
4,Loading successfull,2014-09-25

can be loaded as

logs = LOAD 'log_folder/log_file.csv' USING ...

Split array based on difference with NumPy


I had a NumPy array of numbers, which I had to split based on the change of value.

For example, consider an array as shown below.

values = [112.0, 111.0, 113.0, 111.0, 112.0, 112.0, 112.0, 113.0, 113.0,
       113.0, 114.0, 114 ...

Import postgres table to HDFS using sqoop


Importing data from postgres tables into HDFS using sqoop could be done with the following steps.

Make sure postgres jdbc connector is available in /usr/share/java directory.

To list all available tables in the postgres database

$ sqoop list-tables \
    --connect jdbc:postgresql:// \
    --username myUserName \
    --password myPassword

To ...