使用duplicated与apply
duplicated
apply
apply(df,1,duplicated) [,1] [,2] [,3] [1,] FALSE FALSE FALSE [2,] FALSE TRUE TRUE [3,] FALSE TRUE FALSE
并替换为 NA
NA
df[t(apply(df,1,duplicated))]=NA df label val val1 1 a x z 2 b 3 c d