[R] inserting columns in the middle of a dataframe

[Anupam Tyagi]

I think it should be possible to create the column at the end and then use
"order" on the columns names and indexes to only change the order of column
indexes, rather than having to do operations on the data itself (which will be
very time consuming if the dataset is large). Perhaps people with better R
skills can suggest how to code this. Anupam.