need help with sorting an array

Question

Suppose I have the following array

1.0000    2.0000    0.4231
1.0000    3.0000    0.8050
1.0000    4.0000    0.7116
2.0000    4.0000    0.6682
2.0000    5.0000    0.4460
2.0000    7.0000    0.5818
3.0000    4.0000    0.0977
3.0000    6.0000    0.5989
3.0000    7.0000    0.3237
4.0000    7.0000    0.2882
5.0000    6.0000    0.1456
5.0000    7.0000    0.3168
6.0000    7.0000    0.2767

I want to sort rows according to the elements of column 3 in a descending order. So that the sorted array is like:

1.0000 3.0000 0.8050

1.0000 4.0000 0.7116

2.0000 4.0000 0.6682

3.0000 6.0000 0.5989

.......................................

Note that, if I use 'sortrows' then the array is sorted in a ascending order automatically which I could not change. If I use 'sort', each column is sorted individually which is not what I want. Any help would be highly appreciated.

-Faisal

How is this array stored? You could create a table out of it then using a data view you would be able to sort by any column you want... — G Berdal
– G Berdal, Commented Jul 26, 2010 at 12:00

kennytm · Accepted Answer · 2010-07-26 12:04:27Z

3

To sort in descending order you need a negative column index.

sortrows(a, -3)

answered Jul 26, 2010 at 12:04

kennytm

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High Performance Mark · Accepted Answer · 2010-07-26 11:59:49Z

2

Read the next page of the manual:

sortrows(X,COL) sorts the matrix based on the columns specified in the vector COL.

especially the next sentence after the one I have quoted.

answered Jul 26, 2010 at 11:59

High Performance Mark

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2 Comments

defines Over a year ago

Would vote up except why don't you just post "the next sentence".

High Performance Mark Over a year ago

@Dustin: because I grew tired of cutting and pasting text from the Matlab on-line help. I'm not proud of it, but it was all the strength I could muster at the time.

nuriaion · Accepted Answer · 2010-07-26 12:01:31Z

-1

sortrows(yourArray,3)

answered Jul 26, 2010 at 12:01

nuriaion

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