我以前做过这个计算(见下文):
#Sum for each unique species, FishID and unique stomach content the amount of prey itemsStomach_perc <- count(unique(Stomachdata_2017), vars = c("Species", "FishID", "StomachSp"))Stomach_perc$Occ <- rep(1,nrow(Stomach
我有如下数据:Barium swallow : There is slow transit to the stomach.Conclusion: Normal studyBarium swallow : There is slow transit to the stomach.Conclusion: Normal studyBarium swallow : There is slow transit to the stomach.\\n|\\.$)示例1
Barium swallow