How to load data from structure with user input

A program I am using dumps collected data to a matlab structure with the first sub-structure being called the same as the filename and then the sub-sub-structures are all named consistently regardless of the filename. I'm trying to allow the user to input the filename and then use that to load the 1st sub-structure.

I can assign a filename in the script and assign data to a variable.

s=load('mile_out_45mph_run002.mat')

subs=(s.mile_out_45mph_run002);

subs_X=(subs.X); etc.

What I want is the user to tell me the filename:

filename=input('Enter filename without ".mat": ','s');

filenamemat=[filename,'.mat']

s=load(filenamemat);

subs=(s.filename);

but I get the error Reference to non-existent field 'filename' Which makes sense. It's actually called 'mile_out_45mph_run002'. How do I drill into the structure and get it to recognize that when I put

subs=(s.filename); I mean

subs=(s.mile_out_45mph_run002)

[David Dominic]

Bah! Easy Peasy. I think I tried every combination of ()':" that I could think of except that one. Thanks!

Answer 1

[Adam]

You need to use dynamic string syntax for accessing structure fields - e.g.

subs = s.( filename );

that way 'filename' can be a variable as you want, but it will get interpreted to the string contained in the variable when used as a field name of 's'.

This is shown on http://uk.mathworks.com/help/matlab/matlab_prog/generate-field-names-from-variables.html

I'm not quite sure what your parentheses are meaning though in:

subs = ( s.mile_out_45mph_run002 );

They don't do anything as far as I am aware.