Free Software vs Open Source Software

Although both Open Source Software and Free Software mean that the source code of the software is available, there are subtle differences between the 2 licences in their authority to re-distribute and in the right to work with proprietary software.

Open Source software
- Original author has the final say to whether a user-modified software is distributable or not
- Allowed to work with proprietary software


Free software
- Original author has no power to call whether a user-modified software is distributable or not
- Not allowed to work with proprietary software

Sources:
- http://www.slackbook.org/html/introduction-opensource.html
- http://www.differencebetween.net/technology/difference-between-open-source-and-free-software/

Python: Read excel files with library xlrd

Python is able to read/write excel files with the help fo the xlrd library.

Installing xlrd

1. Download it from here and extract it
2. Start terminal and go to the xlrd extracted directory
3. Type in 'setup.py install' and press enter to start the installation

Sample code

import xlrd

book = xlrd.open_workbook('keyword.xlsx');

print book.nsheets

print book.sheet_names()

sh = book.sheet_by_index(0)

print sh.name, sh.nrows, sh.ncols

Source:
http://stackoverflow.com/questions/3504604/recommend-a-python-library-to-read-excel-xls-files

Making big numbers comprehensible by converting them into personal units

In policy-related discussions, numerical facts are often expressed in big numbers which make them difficult to understand. For example:

The Hong Kong government had a revenue surplus of  $63.4 billion HKD in the 2011-12 fiscal year. [1]

But how much is 63.4 billion HKD?

To a layman, 63.4 billion, being an astronomical figure, only means BIG and the size of 63.4 billion is never fully comprehended.  To enable them to appreciate the size of the number, all that's needed is a little extra information. Knowing that the population of Hong Kong in 2011 is 7.1 million [2], the revenue surplus can now be expressed in personal terms:

The Hong Kong government had a revenue surplus of $63.4 billion HKD in the 2011-12 fiscal year, which is equivalent to $9000 HKD per person.

The size of the revenue surplus immediately becomes comprehensible when its equivalent personal unit is provided. Any person living in Hong Kong would be immediately know that the surplus is just under 1 month of salary for the root class and one can buy 2 iPhone 4S with that amount of money [3].

References:

[1] Hong Kong SAR 2012-2013 Financial Budget
[2] Wikipedia: List of countries by population
[3] iPhone 4 price in 2012 Feb from Apple Store