Matlab efficient for loop possible or many needed? -

for = 1:length(startidx)     j = 1:length(date(startidx(i):cutoffidx(i)))         k = date(startidx(i):cutoffidx(i));         try             shortidx(j)=find(and(and(and(and(and(jam>=1.2,jam<=2.3),expiration==xdates(i)),option_type=='c'),jamsym==1),quote_date==k(j)),1);         catch             warning('not present')             shortidx(j)=0;         end     end end 

let's i = 1:4. on first pass through i, fine. when i = 2, overwriting stored shortidx data created when i 1. j length of each i, , k dates each i. tripped last part of try statement

quote_date==k(j) 

because when i turns 2, j reset 1. though k correct set of dates i, overwriting shortidx variable, instead of appending it. there way me solve efficiently? or need create independent loop each i? thank you.

save 2d array indexed i , j. on each pass of inner loop

shortidx(i, j) = someobscenelylongandstatement; 

for efficiency should preallocate shortidx before loops.

alternatively, make long 1d array, update indices

shortidx(length(startidx)*(i- 1) + j) = ... 

good luck!