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Showing posts from May, 2011

A note on dictionaries in Programming languages

I recently started with learning python. The good thing about python is that everything in python is dynamic. Python is dynamically typed language. What does it means? In C/C++ or Java we need to define the type of a variable before using it. int a; float b; // even Objects need to be defined in Matrix m1; But, python is different in this regard. Here, we can use a variable and its type is decided on first assignment. list # not needed but just for explanation list = [] # creates an empty list Thus, Python decides the type of a variable on its first assignment making it dynamically typed. But, another thing to be careful with in it is that Python is also strongly typed language. Means, once assigned we cant change the type of that variable. In, above python code once list varible is assigned an list object it cant be assigned any other data type. It remains list. Below, is the summarization of different types of languages based on the property we just discussed. stat...

line-by-line processing : Linux Bash

Often we require to process a file content line by line. Linux inherently supports this thorough its powerful shell commands. Lets walk through some of the ways to parse a file line-by-line. First, we can parse a file by catting a file and piping the file output to a while read loop. The following bash script produces it own code as output. Isn't it interesting? code for dumping own file content #!bin/bash cat $0 | while read line do echo $line; done Secondly, using file descriptors we can play a lot with it. But, before we will learn about firl descriptors in brief. Under unix/linux OS, files are referenced, copied, and moved by unique numbers known as file descriptors. 0 stdin It is(devie) usually the keyboard or mouse from where the input comes. 1 stdout It is where output is redirected e.g. screen or file 2 stderr It is where the standard error messages are routed by commands, programs, and scripts. $ some_command 2>&1 this means, the command sends all of ...

Upgrading Ubuntu to Natty Narwhal

I recently upgraded Maverick Meerkat to Natty Narwhal. The new ubuntu is packed with Unity for default desktop session. The Unity brings a lot of improvements with it. Along with improved UI and perceivable improved speed we could see a new scrollbar which takes less space and looks nice. Real gift to Ubuntu lovers!! worth a try !!!