# Increase nonzero values without deleting zeros

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monmatlab on 12 Apr 2017
Commented: David J. Mack on 12 Apr 2017
I have a vector X.
X=[0 0 0 0 1 1 1 1 0 0 0 0 0 0 2 2 2 2 2 2 0 0 0 3 3 3 3 0 0 0 0 0 4 4 4]
I want to increase the values of the nonzero elements in vector X by 10 However, when I do this using the find function I end up just having a vector without the zeros.
Y=X((find(X~=0)))+10;
Y=[11 11 11 11 22 22 ... ]
Is there a way to do this without using a for loop?
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monmatlab on 12 Apr 2017
Edited: monmatlab on 12 Apr 2017
at their initial positions. I want to have the same vector , just with the nonzeros increased by ten

David J. Mack on 12 Apr 2017
Edited: David J. Mack on 12 Apr 2017
Hey monmatlab, simply use logical indexing:
Y = X;
isNonzero = X~=0;
Y(isNonzero) = 10*Y(isNonzero);
or the more compact inplace replacement:
X(X~=0) = 10*X(X~=0);
Greetings, David
##### 2 CommentsShowHide 1 older comment
David J. Mack on 12 Apr 2017
Ah true, the OP stated to increase it... but it's the same idea anyway. Just replace the * by a +.

X = ( X ~= 0 ) .* ( X + 10 );