Replace loop with more efficient procedure to make it faster

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So I'm running this loop:
for n = 1:size(table1)
for m = 1:size(table2)
if table1.WP1(n) == table2.WP1(m) && table1.WP2(n) == table2.WP2(m)
table2.STOPS(n) = table2.STOPS(m);
end
end
end
Which takes really long to process - is there a faster way to do it?

Accepted Answer

Fangjun Jiang
Fangjun Jiang on 19 Aug 2021
Would this give you a clue?
t1=1:3;
t2=(1:4)';
flag=(t1==t2)
  9 Comments
Fangjun Jiang
Fangjun Jiang on 20 Aug 2021
The code I provided is for multiple matching. All can be done in one shot without loops.
If you know there is only one match, the double-for loop could be faster. Your need to use "break" (instead of "continue") to break the loop.
But again, it "could" be faster. If the matching one is the last iteration in the double-for loop, then the "break" has no effect.
Peter Perkins
Peter Perkins on 2 Sep 2021
The double loop is unlikely to be faster for any case. If there is at most one match in table2 for each row of table1, then perhaps ismember would work. But unless these tables are pretty big, the "row == col" strategy is likely to be the fastest.

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