Archives for June 2009

Rebinding Mathematica keys

Out of the box, Mathematica expects the user to press the SHIFT-RETURN to trigger the evaluation of an expression. Because of my hard-wired emacs reflexes, I frequently type CONTROL-RETURN instead. Today I finally did something about that. I rebound the SHIFT-RETURN sequence. Mathematica does not make that easy to do. I found nothing in the [...]

Selecting random observations from SAS datasets

Here are some simple ways to extract various types of random samples from SAS datasets, using only base SAS. Sampling without replacement. A simple way to select N random elements from a dataset without replacement is to first randomly permute the dataset, and then take the first N elements of the permuted dataset. The process [...]