I have a list of ICD9(disease) codes and associated exposure measures. I am interested in a script that would calculate the mean exposure for each ICD9 code and the combined mean for all other codes excluding that code, then attaching those measures, and a count of how many numbers were included in each average, to a table of unique ICD9 codes, such that the final table would look like this: ICD9 code ave_exposure ICD9count otherICD9_ave_exposure otherICD9_count I have been using the gsummary function in the nlme package. Thanks!