adding values to the same column

hi there, I have a matlab question. Ok for example, I have 2 array of 1x350 each, one gives the information of mixture fraction, and the other one gives the information of temperature. For example,

Mix Frac  0.1    0.22    0.32   0.32     0.5     0.2    0.21  0.23  
Temp       300    1200   580    560      1200    1320    1500 1360

What I want to do is to find the mixture fraction of a range of 0.19-0.21, and at the same time gives me the information of the temperature for that mixture fraction. So for example from the above ‘array’, it will create a new variable like below which only gives me the information of the temperature that in the range of the mixture fraction I asked….

Mix Frac     0.2    0.21  
Temp        1320    1500

so i have got an answer for this, which it can be found by

xnMix_frac = xnMix_frac(:);
xnTemp = xnTemp(:);
t = xnMix_frac >= .19 & xnMix_frac <= .21;
out = [xnMix_frac(t), xnTemp(t)];

however, i am running a loop, so the 'out' will get overwritten. as in each loop, the number of xnMix_frac that satisfies the criteria is not the same, so i couldnt use the 'out=[out i+rand]'.

i was wondering if for every loop, it is possible to keep adding the data on the same column of 'out' in the new row and so on?

for example, the first two mix frac and temp value is from the first loop, and the last four from the second loop and so on?

Mix Frac     0.2    0.21  0.2    0.19    0.2    0.2
Temp        1320    1500  1300   1300   1450    1700

thanks!

Answer 1

[James Tursa]

If the loop isn't too big, you could just append it and dynamically increase the size of out in the loop. E.g.,

out = []; % <-- prior to the start of the loop
    :
out = [out; xnMix_frac(t), xnTemp(t)]; % <-- in the loop

But if the loop could be large, then maybe save all of the loop iteration out's in a cell array and then concatenate the cell array at the end of the loop. E.g.

out{loop_index} = [xnMix_frac(t), xnTemp(t)]; % <-- inside the loop
    :
out = vertcat(out{:}); % <-- after the loop is done

[FAISAL]

it works perfectly! thanks!