swapping rows in a matrix

How can i create a matrix which is a copy of an other matrix except 2 rows have to swap.

for example 4*4nmatrix called M how can i create an new matrix which is a copy of M, but the first and the third row are swapped

Answer 1

[Stephen23]

>> X = [1,3]; % rows to swap
>> M = randi(9,4,5)
M =
   6   7   6   2   9
   2   3   2   1   1
   1   6   9   7   9
   4   6   7   5   2
>> W = M;
>> W(X,:) = W(X([2,1]),:)
W =
   1   6   9   7   9
   2   3   2   1   1
   6   7   6   2   9
   4   6   7   5   2

[Adam Danz]

+1 simple & neat

[Narayan Sharma]

what does the [2,1] call for

[Adam Danz]

With the syntax W(X([A,B]),:) row A becomes row 1 and row B becomes row 2.

Indexing is lesson 1 in Matlab.

https://www.mathworks.com/company/newsletters/articles/matrix-indexing-in-matlab.html