CODEWITHSUNDEEP
r
dzadi
dzadi

Reputation: 137

order a column within each group

I have a large data set like this:

 df <- data.frame(group = c(rep(1, 3), rep(5, 3)), member = c(30, 10, 22, 21, 44, 15)) 

 group member
 1     30
 1     10
 1     22
 5     21
 5     44
 5     15

...

I want to order member within each group. The expected output should look like this:

 group member
 1     10
 1     22
 1     30
 5     15
 5     21
 5     44

...

Does anyone have idea about realizing this?

Upvotes: 1

Views: 63

Answers (2)

fmarm
fmarm

Reputation: 4284

You can use the "with" function : first argument is your dataframe and second one is what you want to do with it : order by variable "group" then by variable "member".

df[with(df,order(group,member)),]

Upvotes: 1

Jilber Urbina
Jilber Urbina

Reputation: 61214

Try using ddply from plyr package

> library(plyr)
> ddply(df, .(group), mutate, member=sort(member))
  group member
1     1     10
2     1     22
3     1     30
4     5     15
5     5     21
6     5     44

Upvotes: 0

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