unique / sort in data.frame

Question

I have a data frame like this:

x=c(\"01\",\"01\",\"01\",\"22\",\"22\",\"03\",\"03\",\"03\",\"35\",\"35\")
y=c(\"f\",\"f\",\"f\",\"m\",\"m\",\"m\",\"m\",\"m\"         


        

Answer 1

df2 = df[!duplicated(df), ] # Remove duplicated rows.
df3 = df2[order(df2$spn), ] # Sort by the spn column.

df3
#  spn sex
#1  01   f
#6  03   m
#4  22   m
#9  35   f

Answer 2

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

Answer 3

Use unique then order:

df <- unique(df)
df[order(df$spn), ]

Using dplyr, data.table:

library(dplyr)
unique(df) %>% arrange(spn)
#   spn sex
# 1  01   f
# 2  03   m
# 3  22   m
# 4  35   f

library(data.table)
unique(setDT(df))[ order(spn), ]
#    spn sex
# 1:  01   f
# 2:  03   m
# 3:  22   m
# 4:  35   f