could anyone help me how to select four maximum values of each row in a matrix size(10,8)

I am having a matrix of size(10,8) (% 10 rows and 8 columns)

I want to select 4 maximum values from each row by having the result of matrix size(4,8)(%4 rows and 8 columns)

Could anyone please help me on this.

[Walter Roberson]

This question does not describe what to do in the case of ties.

Answer 1

[KALYAN ACHARJYA]

You can do it in multiple ways, let’s consider, the mat1 is matrix having size 10x8

sort_mat=sort(mat1);
result=sort_mat(7:end,:);

Another way as per @madhan ravi comment

sort_mat=sort(mat1,'descend');
result=sort_mat(1:4,:)

See example

>> mat1=rand(10,8)

mat1 =

    0.2599    0.5499    0.1839    0.3692    0.5752    0.6477    0.7802    0.8176
    0.8001    0.1450    0.2400    0.1112    0.0598    0.4509    0.0811    0.7948
    0.4314    0.8530    0.4173    0.7803    0.2348    0.5470    0.9294    0.6443
    0.9106    0.6221    0.0497    0.3897    0.3532    0.2963    0.7757    0.3786
    0.1818    0.3510    0.9027    0.2417    0.8212    0.7447    0.4868    0.8116
    0.2638    0.5132    0.9448    0.4039    0.0154    0.1890    0.4359    0.5328
    0.1455    0.4018    0.4909    0.0965    0.0430    0.6868    0.4468    0.3507
    0.1361    0.0760    0.4893    0.1320    0.1690    0.1835    0.3063    0.9390
    0.8693    0.2399    0.3377    0.9421    0.6491    0.3685    0.5085    0.8759
    0.5797    0.1233    0.9001    0.9561    0.7317    0.6256    0.5108    0.5502

>> sort_mat=sort(mat1)

sort_mat =

    0.1361    0.0760    0.0497    0.0965    0.0154    0.1835    0.0811    0.3507
    0.1455    0.1233    0.1839    0.1112    0.0430    0.1890    0.3063    0.3786
    0.1818    0.1450    0.2400    0.1320    0.0598    0.2963    0.4359    0.5328
    0.2599    0.2399    0.3377    0.2417    0.1690    0.3685    0.4468    0.5502
    0.2638    0.3510    0.4173    0.3692    0.2348    0.4509    0.4868    0.6443
    0.4314    0.4018    0.4893    0.3897    0.3532    0.5470    0.5085    0.7948
    0.5797    0.5132    0.4909    0.4039    0.5752    0.6256    0.5108    0.8116
    0.8001    0.5499    0.9001    0.7803    0.6491    0.6477    0.7757    0.8176
    0.8693    0.6221    0.9027    0.9421    0.7317    0.6868    0.7802    0.8759
    0.9106    0.8530    0.9448    0.9561    0.8212    0.7447    0.9294    0.9390

>> resul1=sort_mat(7:10,:)

resul1 =

    0.5797    0.5132    0.4909    0.4039    0.5752    0.6256    0.5108    0.8116
    0.8001    0.5499    0.9001    0.7803    0.6491    0.6477    0.7757    0.8176
    0.8693    0.6221    0.9027    0.9421    0.7317    0.6868    0.7802    0.8759
    0.9106    0.8530    0.9448    0.9561    0.8212    0.7447    0.9294    0.9390

>> 

[madhan ravi]

Use sort() with 'descend' option and evoke the first four rows.

[KALYAN ACHARJYA]

Yes, thanks answer added!

[jaah navi]

thanks.

Answer 2

[Guillaume]

As I commented here (please don't ask the same question multiple times, thus wasting people's time), the simplest way in modern matlab (R2017b or later) is with maxk:

result = maxk(yourmatrix, 4)