[R] Changes between R 3.1 vs 3.0.3

[Marc Girondot]

If there a list of changes between 3.1 and 3.0.3 ?

For example, when using levels(xxxx), if xxxx was not a factor, in 3.0.3 
it was changed as a factor but in 3.1 RC it returns NULL.
Same for automatic conversion in numeric for characters used in algebric 
operations.

New way is more strict and is better in my point of view. It will 
prevent unwanted side effect in code.

Thanks a lot

Marc Girondot