ここに書いたことは、混乱まねきそうなので削除。 こちらにまとめなおしました。 ↓ New version : http://d.hatena.ne.jp/t_ume_tky/20130217 1. CHANGE LEVEL OF FACTORS (use "levels" function) levels(factor) = c ("Sun", "Mon" ....) 2. REORDER LEVEL…

○ Extracting indices from data frame by factor. which(df$b %in% factor(c("a","e")) ○ subset data frame by factor. subset(df , b %in% c("a","e")) # b : column name, a,e : factors you want to select %in% operator is useful in this case. %in%…

Sorting factor levels by data frequency of levels table function (arg:factors) returns table class (which seems to be based on numeric vector. Check mode(table(factor(c(1,2,3))))) order function (arg:vector) returns index vector (whose num…