CODEWITHSUNDEEP
matlabstructscatter-plot
Reluctant_Linux_User
Reluctant_Linux_User

Reputation: 343

Making scatter plots from structs in MATLAB

I'm trying to write a bit of code of to make MATLAB scatter plots from variables in a structure. I want to give the code the name of the structure (there will be many of these structures) and then get it to make a scatter plot of two variables. When I try the code below I get an error message saying, "??? Error: File: make_graphs.m Line: 6 Column: 9 The input character is not valid in MATLAB statements or expressions." 

str2stuct= input('Please enter the string for the struct e.g. TMB_RUN_1_data:');

test1=strcat(str2stuct,'.NDROP_max');
test2=strcat(str2stuct,'.input_kappa');

scatter($(test2), $(test1))

I thought that the error message probably meant that I was using the dollar sign in a way which MATLAB doesn't approve of (I've yet to find much use for $ in MATLAB).

I tried it like this:

str2stuct= input('Please enter the string for the struct e.g. TMB_RUN_1_data:');
test1=strcat(str2stuct,'.NDROP_max');
test2=strcat(str2stuct,'.input_kappa');

scatter((test2),(test1))

And got this error:

"??? Error using ==> scatter at 51
Must supply X and Y data as first arguments.

Error in ==> make_graphs at 6
scatter((test2),(test1)) "

I tried it with changing the last line as shown below but got the same error as with the brackets:

scatter(test2,test1)

If I use the literal name as below it works fine.

scatter(TMB_RUN_1_data.NDROP_max,TMB_RUN_1_data.input_kappa)

I've tried a bunch of other things but I am not getting it. I've tried the mathworks pages on scatter but there are no examples that are close to what I am doing. I am really really stuck.

EDIT: I have found a solution but I am aware that this is not considered best practice. If you can simply explain how to do this better that would be good. Answers should be aimed at a moron in a hurry, not an experienced programmer.

Upvotes: 1

Views: 519

Answers (1)

Reluctant_Linux_User
Reluctant_Linux_User

Reputation: 343

Making this the last line works:

scatter(eval(test2),eval(test1))

I am aware that 'eval' is frowned upon and so this probably isn't a good long term answer, works for now. This seems to be the way to get MATLAB to actually read the contents of the strings test1 and test2 into the lines in question.

Upvotes: 0

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