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Matlab: Getting rid of a "Switch/Case" within my code

Answer 1

A:

Could you try using the array for countMsgLength, such that instead of, e.g., countMsgLength4 you increment countMsgLength(4).

Since msgLengthN seem to be matrices, you could form a 3d array, which would be like a cube, if all msgLengthN end up being of the same dimension. You just need to initialize this array at the beginning, and then set the appropriate elements as the code progresse. Alternatively, if msgLengthNs are of different dimensions, you could use a cell array, setting msgLength{N}(countmsgLength(N),:) = instead of msgLengthN(countmsgLengthN,:) like you do above. Just before each use, initialize them to an empty matrix, e.g., at the beginning do

msgLength = {};
for k=1:8
  msgLength{k} = [];
end

or, if you know dimensions ahead of time, to a zero matrix

msgLength = {};
for k=1:8
  msgLength{k} = zeros([rows cols]);
end

Other than this, without some extra explanation it seems difficult to decypher what you're trying to do.

mbudisic 2010-07-27 23:55:13

Answer 2

+5 A:

The answer is, DON'T use variables like this, with numbers built into the names. It forces you to write messy code like this. Then later on, you will find yourself desperately trying to debug that code. Eventually, you will find the error, probably in a copy/paste error, where you have typed an incorrectly numbered variable name.

Instead, use a vector, a cell array, a struct, etc. Store your information in arrays, then index into that array/vector/cell/struct. Your code will get simpler, easier to debug, shorter.

woodchips 2010-07-28 00:30:23

Thanks. I am new to matlab and programming in general, but the consensus seems ot be that this is the best way to go.

Maxwell 2010-07-28 18:04:46

Answer 3

A:

Here's a way to get rid of the switch/case. However, it may be more useful for you if you explained more what your data looks like and what you would like to achieve. Most likely, this whole analysis can be simplified a lot.

countmsgLength = ones(9,1); %# countmsgLength(1) are the counts for to case 0
msgLength = cell(9,1);


for x= 1:length(firstinSeq)
        for y= 1:length(littledataPassed)
          if firstinSeq(x,1)== littledataPassed(y,1) && firstinSeq(x,2)== littledataPassed(y,2)
            switchNum = firstinSeq(x,3); %# switchNum is 0...8

                indexStop = find(firstinSeq(x,4) ~= littledataPassed(y:length(littledataPassed),4), 1, 'first');
                for z= 0:switchNum-1 %# if switchNum <2, the loop will execute once
                indexProcess = find((littledataPassed(y:y+indexStop-1,6) == 1 & ... 
                   littledataPassed(y:y+indexStop-1,2) == firstinSeq(x,2) & ... 
                   littledataPassed(y:y+indexStop-1,5) == z), 1, 'first'); 
                if isempty(indexProcess)
                   msgLength{switchNum+1}(countmsgLength(switchNum+1),:)= [firstinSeq(x,:) [0 0 0 0 0 0]];
                else msgLength{switchNum+1}(countmsgLength(switchNum+1),:)= [firstinSeq(x,:) littledataPassed(y+indexProcess-1,:)];
                end
                countmsgLength(switchNum+1)= countmsgLength(switchNum+1) + 1;
                end %# loop z
          end %# if
      end %# loop y
end %# loop x

Jonas 2010-07-28 08:08:05

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Matlab: Getting rid of a "Switch/Case" within my code

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