R help - May 2006 - sort the values of members and obtain their ranks within groups

Dear all,

I would like to sort the values of "member" for each group, and obtain
a
variable to indicate its rank within the group.

For example, we have original dataset as follows:

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

  group member
1     1     30
2     1     10
3     1     22
4     5     21
5     5     44
6     5     15

After sorting the variable "member", we want the dataset like this:

  group member order
1     1     30     3
2     1     10     1
3     1     22     2
4     5     21     2
5     5     44     3
6     5     15     1

I already searched the R helper archives, but failed to find the proper
answers.

Could you please kindly give me some suggestions, except using loop because
of larger sample size?  Thanka a lot.


Best regards,

Zhen Zhang

	[[alternative HTML version deleted]]

> x
  group member
1     1     30
2     1     10
3     1     22
4     5     21
5     5     44
6     5     15
> x$order <- NA
> invisible(tapply(seq(nrow(x)), x$group, function(y) x$order[y] <<-
rank(x$member[y])))
> x
  group member order
1     1     30     3
2     1     10     1
3     1     22     2
4     5     21     2
5     5     44     3
6     5     15     1
>

On 5/22/06, Zhen Zhang <momozilla@gmail.com>
wrote:
>
> Dear all,
>
> I would like to sort the values of "member" for each group, and
obtain a
> variable to indicate its rank within the group.
>
> For example, we have original dataset as follows:
>
> df <- data.frame(group = c(rep(1, 3), rep(5, 3)),
> member = c(30, 10, 22, 21, 44, 15))
>
> group member
> 1     1     30
> 2     1     10
> 3     1     22
> 4     5     21
> 5     5     44
> 6     5     15
>
> After sorting the variable "member", we want the dataset like
this:
>
> group member order
> 1     1     30     3
> 2     1     10     1
> 3     1     22     2
> 4     5     21     2
> 5     5     44     3
> 6     5     15     1
>
> I already searched the R helper archives, but failed to find the proper
> answers.
>
> Could you please kindly give me some suggestions, except using loop
> because
> of larger sample size?  Thanka a lot.
>
>
> Best regards,
>
> Zhen Zhang
>
>        [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help@stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide!
> http://www.R-project.org/posting-guide.html
>


-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390 (Cell)
+1 513 247 0281 (Home)

What is the problem you are trying to solve?

	[[alternative HTML version deleted]]

See if this does what you want:
 
> cbind(df, rank=ave(df$member, df$group, FUN=rank))
  group member rank
1     1     30    3
2     1     10    1
3     1     22    2
4     5     21    2
5     5     44    3
6     5     15    1

Andy

  _____  

From: r-help-bounces at stat.math.ethz.ch on behalf of Zhen Zhang
Sent: Mon 5/22/2006 6:40 PM
To: R-help at stat.math.ethz.ch
Subject: [R] sort the values of members and obtain their ranks within groups
[Broadcast]



Dear all, 

I would like to sort the values of "member" for each group, and obtain
a
variable to indicate its rank within the group. 

For example, we have original dataset as follows: 

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

  group member 
1     1     30 
2     1     10 
3     1     22 
4     5     21 
5     5     44 
6     5     15 

After sorting the variable "member", we want the dataset like this: 

  group member order 
1     1     30     3 
2     1     10     1 
3     1     22     2 
4     5     21     2 
5     5     44     3 
6     5     15     1 

I already searched the R helper archives, but failed to find the proper 
answers. 

Could you please kindly give me some suggestions, except using loop because 
of larger sample size?  Thanka a lot. 


Best regards, 

Zhen Zhang 

        [[alternative HTML version deleted]] 

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