R help - Mar 2011 - Ordering data.frame based on class

Dear R helpers

Suppose I have a data.frame as given below -

my_dat = data.frame(class = c("XYZ", "XYZ", "XYZ",
"XYZ", "XYZ","ABC", "ABC",
"ABC", "ABC", "ABC" ),  var1 = c(20, 14, 89, 81,
17, 44, 36, 41, 11, 36), var2 = c(1001, 250, 456, 740, 380, 641, 111, 209, 830,
920))
> my_dat
   class var1 var2
1    XYZ   20 1001
2    XYZ   14  250
3    XYZ   89  456
4    XYZ   81  740
5    XYZ   17  380
6    ABC   44  641
7    ABC   36  111
8    ABC   41  209
9    ABC   11 
 830
10   ABC  20  920 

I wish to sort above data.frame class-wise on var1. Thus, Ineed to get


class                    var1        var2

 
 
  XYZ  
  14
  250
 
 
  XYZ  
  17
  380
 
 
  XYZ  
  20
  1001
 
 
  XYZ  
  81
  740
 
 
  XYZ  
  89
  456
 
 
  ABC  
  11
  830
 
 
  ABC  
  20
  920
 
 
  ABC  
  36
  111
 
 
  ABC  
  41
  209
 
 
  ABC  
  44
  641
 

Kindly guide

Vincy



	[[alternative HTML version deleted]]

Try this:

my_dat[order(my_dat$class, -my_dat$var1, decreasing = TRUE),]

On Mon, Mar 28, 2011 at 5:55 PM, Vincy Pyne <vincy_pyne at yahoo.ca>
wrote:
> Dear R helpers
>
> Suppose I have a data.frame as given below -
>
> my_dat = data.frame(class = c("XYZ", "XYZ",
"XYZ", "XYZ", "XYZ","ABC",
"ABC", "ABC", "ABC", "ABC" ),? var1 =
c(20, 14, 89, 81, 17, 44, 36, 41, 11, 36), var2 = c(1001, 250, 456, 740, 380,
641, 111, 209, 830, 920))
>
>> my_dat
> ?? class var1 var2
> 1??? XYZ?? 20 1001
> 2??? XYZ?? 14? 250
> 3??? XYZ?? 89? 456
> 4??? XYZ?? 81? 740
> 5??? XYZ?? 17? 380
> 6??? ABC?? 44? 641
> 7??? ABC?? 36? 111
> 8??? ABC?? 41? 209
> 9??? ABC?? 11
> ?830
> 10?? ABC? 20? 920
>
> I wish to sort above data.frame class-wise on var1. Thus, Ineed to get
>
>
> class??????????????????? var1??????? var2
>
>
>
> ?XYZ
> ?14
> ?250
>
>
> ?XYZ
> ?17
> ?380
>
>
> ?XYZ
> ?20
> ?1001
>
>
> ?XYZ
> ?81
> ?740
>
>
> ?XYZ
> ?89
> ?456
>
>
> ?ABC
> ?11
> ?830
>
>
> ?ABC
> ?20
> ?920
>
>
> ?ABC
> ?36
> ?111
>
>
> ?ABC
> ?41
> ?209
>
>
> ?ABC
> ?44
> ?641
>
>
> Kindly guide
>
> Vincy
>
>
>
> ? ? ? ?[[alternative HTML version deleted]]
>
>
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>
>


-- 
Henrique Dallazuanna
Curitiba-Paran?-Brasil
25? 25' 40" S 49? 16' 22" O