Can anyone please let me know which is the best software in ubuntu to plot graph against data??
A program which in my opinion is far superior to Calc or matplot lib, is Veusz. It has a simple graphical interface, and can produce beautiful plots (allmost all graphs I publish now come from veusz as you can export as PDF and SVG vectored images allow scaling without pixelation, combined with the great quality).
I was using Octave for a while. Is a perfect alternative for Matlab.
I always use desmos.com. It's an "online graphing calculator".
it has nothing to do with ubuntu but it's best for your needs!
direct link: https://www.desmos.com/