R: Calculating cumulative number of unique entries
问题 I have a data frame from several experiments. I am looking to calculate cumulative number of unique values obtained after each successive experiment. For example, consider: test <- data.frame(exp = c( rep("exp1" , 4) , rep("exp2" , 4), rep("exp3" , 4) , rep("exp4" , 5) ) , entries = c("abcd","efgh","ijkl","mnop", "qrst" , "uvwx" , "abcd","efgh","ijkl" , "qrst" , "uvwx", "yzab" , "yzab" , "cdef" , "mnop" , "uvwx" , "ghij")) > test exp entries 1 exp1 abcd 2 exp1 efgh 3 exp1 ijkl 4 exp1 mnop 5