Removing data from an array using subsets

Hello, I have a 1x200 matrix where I'd like to simply remove all 0's then use that data in a follow on equation. Below is a short example:

x = [0;0;0;0;1;1;1;0;1;1]
NewPoints = prod(x)

I believe if I can make a subset of x that removes all the 0's but am having trouble. Thanks for any help!

Answer 1

[Voss]

Use logical indexing to identify and remove the zero-elements from x:

x = [0;0;0;0;1;1;1;0;1;1];
x(x == 0) = [];

[Daniel McDonald]

Thank you, that worked!

[Steven Lord]

Identifying candidates to remove is one way to solve this problem. Identifying candidates to keep is another.

x = [0; 0; 0; 0; 1; 1; 1; 0; 1; 1];
xRemove = x; % Make a copy of x so we can look at the original later
toRemove = x == 0;
xRemove(toRemove) = []

xRemove = 5×1

1 1 1 1 1

toKeep = x ~= 0;
xKeep = x(toKeep)

xKeep = 5×1

1 1 1 1 1

If you look at the elements of x and the two masks you can see that each element is selected by either toRemove or toKeep, not both and not neither.

showMasks = table(x, toRemove, toKeep)

showMasks = 10×3 table
    x    toRemove    toKeep
    _    ________    ______

    0     true       false 
    0     true       false 
    0     true       false 
    0     true       false 
    1     false      true  
    1     false      true  
    1     false      true  
    0     true       false 
    1     false      true  
    1     false      true