McGill_Bian 如题,代码如下,把等号改了就可以了 test = data.frame(rnorm(12^2, 0, 2)) for(i in nrow(test)){ ifelse(test[i,1]>0, test[i,2]='p', test[i,2]='n') }
tctcab McGill_Bian ifelse用错了,去看help(ifelse) test = data.frame(val=rnorm(122, 0, 2)) test$pn = ifelse(test$val > 0, "p", "n") head(test) ## result val pn 1 0.4456782 p 2 -2.1963679 n 3 -0.2062692 n 4 -0.5688538 n 5 2.3382969 p 6 0.3015280 p