What is the purpose of environments in R and when I need to use more than one?
r
Solution
The idea of environments is important and you use them all the time, mostly without realizing it. If you are just using R and not doing anything fancy then the indirect use of environments is all that you need and you will not need to explicitly create and manipulate environments. Only when you get into more advanced usage will you need to understand more. The main place that you use (indirectly) environments is that every function has its own environment, so every time you run a function you are using new envirnments. Why this is important is because this means that if the function uses a variable named "x" and you have a variable named "x" then the computer can keep them straight and use the correct one when it needs to and your copy of "x" does not get over written by the functions version.
Some other cases where you might use environments: Each package has its own environment so 2 packages can both be loaded with the same name of an internal function and they won't interfere with each other. You can keep your workspace a little cleaner by attaching a new enironment and loading function definitions into that environment rather than the global or working environment. When you write your own functions and you want to share variables between functions then you will need to understand about environments. Environmets can be used to emulate pass-by-reference instead of pass-by-value if you are ever in a situation where that matters (if you don't recognize those phrases then it probably does not matter).
Problem
This is a basic R question: R has the concept of environment. So what purpose does it have, when do I need to start more then one and how do I switch between them? What is the advantage of multiple environments (other then looking up content of .Rdata file)?