Dear Shmuel,   Sorry for my delayed response. Thanks a lot.  I have 32K data like this. I wanna add one column with country name based on domain of first email address. If domain is like .edu; .com etc then leave as empty. Thanks again, Type Authors Name Source Language Author Keywords Email Addresses J Jo, S; Kim, S; Shin, DH; Kim, MS Jo, Seri; Kim, Suwon; Shin, Dong Hae; Kim, Mi-Sun JOURNAL OF ENZYME INHIBITION AND MEDICINAL CHEMISTRY English SARS-CoV; SARS-CoV 3CLpro; flavonoid; FRET; inhibitory compounds dhshin55@ewha.ac.kr; shfwk31@ewha.ac.kr J Beury, D; Flechon, L; Maurier, F; Caboche, S; Varre, JS; Touzet, H; Faure, K; Dubuisson, J; Hot, D; Guery, B; Goffard, A Beury, Delphine; Flechon, Lea; Maurier, Florence; Caboche, Segolene; Varre, Jean-Stephane; Touzet, Helene; Faure, Karine; Dubuisson, Jean; Hot, David; Guery, Benoit; Goffard, Anne JOURNAL OF CLINICAL VIROLOGY English Human coronavirus; Whole genome sequencing; Hematopoietic cell transplant; Care-associated infections; Phylogenetic analyses delphine.beury@pasteur-lille.fr; lea.flechon.etu@univ-lille.fr; florence.maurier@pasteur-lille.fr; segolene.caboche@pasteur-lille.fr; jean-stephane.varre@lifl.fr; helene.touzet@lifl.fr; karine.faure@univ-lille.fr; jean.dubuisson@ibl.cnrs.fr; david.hot@pasteur-lille.fr; Benoit.Guery@unil.ch; anne.goffard@univ-lille.fr J Checovich, MM; Barlow, S; Shult, P; Reisdorf, E; Temte, JL Checovich, Mary M.; Barlow, Shari; Shult, Peter; Reisdorf, Erik; Temte, Jonathan L. JOURNAL OF THE AMERICAN MEDICAL DIRECTORS ASSOCIATION English Long-term care; acute respiratory infection; rapid influenza diagnostic testing; influenza mary.checovich@fammed.wisc.edu   ... View more

Thanks Shmuel, So, I have to list all countries like 'nl'='Netherlands'.  What if there are more than one email addresses in one cell? I only need to use the first email address. Please advise me how I can deal in that case.    Thanks again, Epi ... View more

Thank you Ballardw,    I also tried the following code to adjust the influence of sex and work type.   proc glm data=data; class sex work; weight sex work; model Sickdays=Pain1 Pain2 Pain3 Pain4; run;   It also didn't work. It said "weight by sex*sex "but even didnt produce parameter estimates. Now thinking maybe better to check the multi regression model fit including sex and work as an independent variable and weight only by age, if there is no other solution to control sex and worktype at the same time. Thanks again.     ... View more

Thank you very much for your quick response.   Does it mean that two variables cant be used as a weight in linear regression? For example,  I want to check the relation between sick days and pain intensity. So I assume that first) older age people would be more important than younger age and second) people with higher Body Mass Index (BMI) is more likely to have sick days than those with lower BMI. In that case, shouldn't I adjust (weight)  both age and BMI to build regression model for sick days and pain? If one than one variable cant be used at the same time, is there any other solution for this? Thanks again,     ... View more