how do I index a vector with another vector without the use of a for loop

For my matlab homework, given a character vector of 1x(6N) and a logical vector of 1xN, I have to make a function that returns a 1xP vector of the characters that corrrespond to the false values of the logical vector and a 1xM vector of the roginial positions of the characters that correspond to the true values of the logical vector.

Example:

events = 'TRACK ​CYCLI ​SWIMM ​BOXIN ​DIVIN FENCI ' 
belong = [​true​ ​false​ ​true​ ​false​ ​true​ ​true​] 
[wrong, positions] = eventList(events, belong) 
wrong → 'CYCLI BOXIN ' 
positions → [​1​ ​3​ ​5​ ​6​] 

I am able to do everything but return the characters in wrong beyond the first six characters. Here is my code:

function [wrong,positions] = eventList(events,belong)
positions=find(belong==true)
y=1:6:length(events)
z=y(find(belong==false))
len(1:length(events))=true
len(z:z+5)=false
wrong=events(find(len==false))
end

I'm not sure how to change line six so that it uses every value in z instead of only the first value without the use of a for loop.

Answer 1

[Stephen23]

>> idx = ~reshape(repmat(belong,6,1),1,[]); % or use REPELEM.
>> events(idx)
ans = CYCLI BOXIN
>> find(belong)
ans =
   1   3   5   6