r - 在 data.frame 中唯一/排序

Question

我有一个这样的数据框:

x=c("01","01","01","22","22","03","03","03","35","35")
y=c("f","f","f","m","m","m","m","m","f","f")
df=data.frame(spn=x, sex=y)

似乎:

   spn sex
1   01   f
2   01   f
3   01   f
4   22   m
5   22   m
6   03   m
7   03   m
8   03   m
9   35   f
10  35   f

我想做的是对 df$spn 进行排序，让它只出现一次。适当的 df$sex 以及，例如:

   spn sex
1  01   f
2  03   m
3  22   m
4  35   f

我怎么能那样做？非常感谢!

Answer 1

df <- df[order(df$spn), ]
> df[!duplicated(df), ]
  spn sex
1  01   f
6  03   m
4  22   m
9  35   f