[R] Sorting in R

[Jim Robison-Cox]

On Wed, 21 Jun 2000, Art Salwin wrote:

> How do you sort one vector using another vector as a sort
> key?  Sort of equivalent
> to sorting rows of a spreadsheet using one of its columns as
> key.  Here's a simple example:
> 
> name<-c("Joe","Sue","Mary")
> age<-c(22, 57, 13)
> zipcode<-(50854, 20617, 91234)

For brevity, I'd make these into a data frame:
 spsheet <- data.frame(name,age,zip)

> If we sort the name vector in zipcode order we should get
> mary, joe, sue

 name(order(zip))
or
spsheet[order(zip),]

> If we sort name in age order we should get sue, joe, mary

   name(order(age))
or
spsheet[order(age),]


> Having secondary keys to break ties would be nice, as would
> the ability to sort (in this example)
> all 3 vectors at once.

 That's a bit harder,  I would sort first on the secondary column, then
the primary.  Or tertiary - secondary - primary.

 If primary is name, secondary age, tertiary zip:
spsheet <- spsheet[order(zip),]
spsheet <- spsheet[order(age),]
spsheet[order(name),]
 
  I hope someone has a better way.

> Any help appreciated.
> -- 
> Art Salwin
> salwin at mitretek.org
> (202) 863-2985
> (202) 863-2988 (fax)
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Jim Robison-Cox               ____________    
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