How do I get a group minimum over level combinations of factors?

I would like to find minimum values within groups. In stata, I think it is simply "by group,开发者_高级运维 sort : egen minvalue=min(value)"... I tried to mess around with ave and rowsum, but to no avail. ave(value, group, FUN=min) did not work.

Sorry this answer is a little late but, in case you are still looking for the answer or for future searchers here goes....

You are onto the right track with the -by- command. Here is what I'd do to find the lowest price of cars in the auto.dta dataset by domestic/foreign grouping.

sysuse auto, clear
bysort foreign : egen minprice = min(price)

What this does is create a new variable 'minprice' that holds the minimum price for domestic cars if a given car (observation) is domestic and vice versa for foreign cars. So this new variable with have just two values in this example and you can check that by doing:

tabulate minprice

Depending on why you wanted to find the minimum values by group this may not be what you had in mind but hopefully someone finds it helpful.