How do I create a random row matrix with some fixed positions?

Hello everyone,

I want to create a row matrix with some fixed positions. For example,

>> randperm(20)

ans =

    11     3    14     5     4     8    13    15    10     6    18     9    20    16    17     7    12     2    19     1

But I want to keep some positions in this array. For example, the first three positions of the array should always be 11 3 and 14, regardless of how much I use the randperm (20) command. How can I do this? It is possible?

Answer 1

[Andrei Bobrov]

a = [ 11     3    14];
b = 1:20;
c = setdiff(b,a);
n = numel(c);

out = [a, c(randperm(n))];

[Abdullah Türk]

Thank you vey much Andrei Bobrov.

I've done the process I wanted to do with your coding.