myuw <- read.csv("myuw-COM_482_A_autumn_2020_students.csv") gs <- read.delim("student_information.tsv") ## these are students who dropped the class (should be empty) gs[!gs$Your.UW.student.number %in% myuw$StudentNo,] ## these are students who are in the class but didn't reply to the form myuw[!myuw$StudentNo %in% gs$Your.UW.student.number,] ## read all the folks who have been called and see who is missing from ## the google sheet call.list <- unlist(lapply(list.files(".", pattern="^attendance-.*tsv$"), function (x) { d <- read.delim(x) strsplit(d[[2]], ",") }) ) present <- unique(call.list) present[!present %in% gs[["Your.username.on.the.class.Discord.server"]]] ## and never attended class.. gs[["Your.username.on.the.class.Discord.server"]][!gs[["Your.username.on.the.class.Discord.server"]] %in% present]