set zero to multiple values in a matrix

[BOKU]

Hello,

i would like to know if there is a fast way to select some items of a 
indexed matrix?

this is not working in my case ?!

sel =

    [14   19   23   24   25   29]

lab is a 301x301 labeled matrix

numel(unique(lab))
   ans =  47

I want to do something like

lab(lab==!sel)=0

do I really need to go through a loop for doing this?

greets chris