Tag: python

Melbourne Tweet Cloud


URL: words.yznotes.com

If a picture is worth a thousand words, then the picture on the left should be an equivalent to 1,100 words, at least :)

This App collects tweets posted within 10km of Melbourne CBD, does some Natural Language processing and renders top 100 words into a Word Cloud.
Refreshed every 10 minutes 24/7. Ran on Amazon Web Services.

This is Work in Progress, there will be new features added with time.

Auditing and Analysing Image (Photo) Sizes

IPython Notebook File

Environment: Python 3.4
Main Libraries Used: reportlab, pandas, vincent

Interactive Data Analysis Setup on AWS


Current setup includes: Linux Ubuntu Server on EC2 (Elastic Computing Cloud) with Postgres and Python Data Analysis Tools (IPython, Numpy, Pandas, etc.) + Elastic IP + Load Balancer + EBS (Elastic Block Store)


Plotting zipline algorithms with matplotlib

Dual Moving Average Crossover algorithm buys stock once its short moving average crosses its long moving average (indicating upwards momentum) and sells it once the averages cross again, indicating downwards momentum (source: zipline)


Oracle Wallet Set Up

Environment: Windows XP SP3, Oracle Client 11.1.0

Step 1:


Open your sqlnet.ora file (mine is located in C:\oracle\product\11.1.0\db_1\NETWORK\ADMIN) and add section below at the end:

The DIRECTORY parameter in line 5 determines  where your wallet files will be created. It has to be an absolute path. To keep it simple I set mine to the same directory where sqlnet.ora, listener.ora and tnsnames.ora files sit.


Step 2:
Run shell command mkstore -wrl “C:\oracle\product\11.1.0\db_1\NETWORK\ADMIN” -create (see below). You will be asked to set up a password for the wallet. This password has no relation to the TNS credentials, it’s to protects wallet itself. The directory path has to be the same as in previous step (in my case it’s C:\oracle\product\11.1.0\db_1\NETWORK\ADMIN)


You will notice wallet files created in that directory:




Step 3:

Open tnsnames.ora file (usually in the same directory where sqlnet.ora sits), and create a new TNS entry which you will be using with the wallet. Normally you would want to just copy an exiting entry giving it a new alias. In example below I create a TNS entry PRDSPW by copying an existing TEST one:



Step 4:

Run shell command mkstore -wrl “C:\oracle\product\11.1.0\db_1\NETWORK\ADMIN” -createCredential PRDSPW dummy_user dummy_pass (see below), where PRDSPW is the special TNS name we created in Step 3, dummy_user – database username, dummy_pass – database password. You will be asked to provide wallet password that we set up in Step 2. Path (C:\oracle\product\11.1.0\db_1\NETWORK\ADMIN) – is the same as in all previous steps.



All done.

Now if you run command mkstore -wrl “C:\oracle\product\11.1.0\db_1\NETWORK\ADMIN” -listCredential it will list a new wallet entry that we just created:


From now on you can connect to PRDSPW by calling wallet entry without exposing your database user name and password:




Command to delete an individual credential: