# [R] SORTING Arrays by index value

Jonathan Baron baron at cattell.psych.upenn.edu
Tue Feb 4 18:26:04 CET 2003

```On 02/04/03 11:46, Mark G Orr wrote:
>Hello, I'm somewhat new to R.  I've searched the archive for the last year
>and tried to consult the manual pages for the following problem, but did
>
>I want to sort an array by the index values.  Here is the array

Looks like a matrix (which is, I guess, a type of array).

To sort by the first column, try

acc.gp.bl.wtmn[order(acc.gp.bl.wtmn[,1],]

>>acc.gp.bl.wtmn
>        Gp17       Gp4
>1  0.5703125 0.6406250
>10 0.7812500 0.7109375
>11 0.8046875 0.7343750
>12 0.8359375 0.7890625
>13 0.8515625 0.7109375
>14 0.8281250 0.7343750
>15 0.8671875 0.7812500
>16 0.8125000 0.7578125
>17 0.7734375 0.7500000
>18 0.8000000 0.7800000
>19 0.8700000 0.7300000
>2  0.8046875 0.7265625
>20 0.8300000 0.7400000
>21 0.7500000 0.8000000
>22 0.7700000 0.7600000
>23 0.8200000 0.7800000
>24 0.7600000 0.7400000
>25 0.8100000 0.8000000
>3  0.7578125 0.7812500
>4  0.8203125 0.7890625
>5  0.7890625 0.7421875
>6  0.7265625 0.7812500
>7  0.8125000 0.7421875
>8  0.8515625 0.7265625
>9  0.8203125 0.6953125
>
>My question is:  How do I sort by the first index (the values are 1:25)
>without losing the associated values per index value for the two
>columns(Gp17 and Gp4).  I want ascending order (1:25) of the index values.
>
>
>-Mark Orr
>
>
>
>Postdoctoral Fellow
>Psychology Dept.
>Carnegie Mellon Univ.
>Pittsburgh, PA 15213
>
>______________________________________________
>R-help at stat.math.ethz.ch mailing list
>http://www.stat.math.ethz.ch/mailman/listinfo/r-help

--
Jonathan Baron, Professor of Psychology, University of Pennsylvania
R page:               http://finzi.psych.upenn.edu/

```