(MATLAB) On drawing elements randomly from vectors and rows randomly from matrices without replacement in for loops

So, two related questions for code I'm writing for an experiment I'm building in MATLAB. Firstly, I have a 20 row column vector, called block1 (with a number in each of the 20 slots). I want to draw a number randomly from the vector without replacement and repeat this until there are no numbers left in the vector (so 20 times total). I have the following line within a for loop (which is set to run for 20 iterations), which draws the random number from the vector and sets it equal to variable rand_num: rand_num = randsample(block1,1,false) It draws the random number just fine, but the problem is that the draw without replacement part doesn't work. Initially I thought this was because the vector was reset at the beginning of each iteration of the for loop. To make sure, I debugged and found that even when I stop the for loop before the first iteration finishes (and after the random number has been drawn), there are still 20 numbers in the vector (when there should be 19). Any ideas as to how I can fix this?

The second question is as follows. For the same experiment, I have a 20 by 6 matrix called pick_matrix. During each iteration of the same for loop as above, I want to pick one row at random from the matrix (including every element in that row; so 6 elements total for each row) without replacement and assign that row to variable random_row. I figured out the code to pick a row at random and assign it to random_row, but I'm having the same problem as with the last question: the without replacement part isn't working. Any ideas?

Many thanks!

G