A way to incorporate the name of one vairable into another?

I have 5 arrays, A1, A2, A3, B, and C. I have an algorithm that finds matches between values in the A arrays and the B and C arrays then collects them in a matrix "match_results". Is there a way to incorporate the name of the A array into the match_results name? That is have the code output "match_results_A1", etc, after running?

Another way of asking: Say I have arrays A, B C, D and E. I want my code to compare A to D and E, then output a match_results matrix, then compare B to D and E and output a second match matrix, then the same for C. Ideally, I would end up with three matrices labeled "match_A" "match_B" and "match_C". Is there a way to do this, or am I just going to get multiple instances of "DON'T DO THIS! http://matlab.wikia.com/wiki/FAQ#How_can_I_create_variables_A1.2C_A2.2C....2CA10_in_a_loop.3F"?

Answer 1

[Image Analyst]

To me, that seems like a very bad idea , something along the lines of http://matlab.wikia.com/wiki/FAQ#How_can_I_create_variables_A1.2C_A2.2C....2CA10_in_a_loop.3F

[Ben]

Yes, I've read that thread multiple times. Can you explain exactly why it is such a bad idea? That thread comes up each time someone asks a question about variable names. I need my outputs to tell me which array the results came from. Can you suggest an alternative?

[Image Analyst]

If you don't know the name of a variable, how can you refer to it later on? If you do know the names that will ultimately be chosen, then you have no need to create the variable name on the fly.

Like if you have A1, A2, A3, B, and C and want to create a variable named match_results_A1_A2_A3_B_C, then how will you know what it's called. If you know that you have those arrays and that the variable will be called match_results_A1_A2_A3_B_C, then just use that - don't create the name dynamically on the fly.

But let's say that you're going to change the names of the arrays early in your code to S, T, and U and now you're array would need to be called match_results_S_T_U. But how are you going to refer to it if the name always keeps changing? It's a bookkeeping nightmare.

[Ben]

Ah, I see. Well, I have two vectors 'calib_nu' and 'pkht' that are always the same. Other variables get compared to these two and I have to specify the third input vector each time. I'd like the output to reflect the name of the third vector. I tell it to run on 'ca627', I'd like the matrix to be called 'match_ca627' so I can then run it on 'ca628' and get a matrix 'match_ca628'. The third input vector is different each time as the data rolls out.

[Star Strider]

Not certain what you’re doing, but consider using a Cell Array. It may do everything you want without all the horrible inconvenience and inefficiency of multiple numerical matrices with similar names.

[Ben]

I'm not sure how to explain more clearly. I work in spectroscopy.

I have two data vectors: "calib_nu" a frequency value, and "pkht" a corresponding intensity. I then have various predictions of what frequencies might be present based on isotopic substitution of a molecule such as 'ca627'. The 627 and 628 above refer to isotopes not a numerical array designator, others are 728, 636, 638...

Currently my script takes one of the prediction vectors, say 'ca626', and checks for matches in 'calib_nu' then outputs a 'match_results' matrix containing a column each from 'ca626' 'calib_nu' and 'pkht'. I then have to manually change the variable name to 'match_ca626' so I can run the script on one of the other predictions. I would just like the script to output the 'match_ca626' automatically so I don't have to worry about 'match_results' being overwritten by accident before I remember to change the name.

[Image Analyst]

One way to do it is to use dynamic structure names. I don't like them but they are supported and are the preferred way, much more so that what you've asked to do. See http://www.mathworks.com/matlabcentral/answers/94573-how-can-i-dynamically-extract-fields-from-a-structure-and-create-variables-in-the-matlab-workspace-u

or http://www.mathworks.com/matlabcentral/answers/?term=dynamic+structure+names

[Ben]

Ok. I'll look into alternatives. Thanks for your responses.