MATLAB: Pattern matching problem

Question

I realize my previous post was way too long so here is a simpler version:

%callback for listbox1
%expirement%
pattern1 = 'SHC';
pattern2 = 'SLR';
pattern3 = 'RHA';
indexselected = get(handles.listbox1,'Value');
list = get(handles.listbox1,'String');
itemselected = list{indexselected};
 if regexp(itemselected, pattern1)
    [substance,substance]=xlsread('C:\Users\ecorbett\Documents\VCoachData\Labels\SHC.xlsx','Sheet 1','A1:A10000');
    set(handles.listbox3,'string',substance);
    msgbox('The listbox has been updated.','Update Complete','help');
 elseif  regexp(itemselected, pattern2)
   [substance,substance]=xlsread('C:\Users\ecorbett\Documents\VCoachData\Labels\SLR.xlsx','Sheet 1','A1:A10000');
    set(handles.listbox3,'string',substance);
    msgbox('The listbox has been updated.','Update Complete','help');
 elseif regexp(itemselected, pattern3)
     [substance,substance]=xlsread('C:\Users\ecorbett\Documents\VCoachData\Labels\RHA.xlsx','Sheet 1','A1:A10000');
    set(handles.listbox3,'string',substance);
    msgbox('The listbox has been updated.','Update Complete','help');
end

the strings in listbox1 are file names:

SHC_RL_S1_0004_v1.59806163.avi SHC_RL_S2_0004_v1.59806163.avi RHA_RL_S3_0004_v1.59806163.avi RHA_LL_S1_0004_v1.59806163.avi SLR_RL_S3_0004_v1.59806163.avi SLR_LL_S1_0004_v1.59806163.avi

right now the code produces no errors but does not update listbox3

Answer 1

I would use STRFIND instead of REGEXP.

list = 'SHC_RL_S1_0004_v1.59806163.avi SHC_RL_S2_0004_v1.59806163.avi RHA_RL_S3_0004_v1.59806163.avi '
pattern1 = 'SHC';
if strfind(list,pattern1)
   disp('Found it!')
end

But now try with:

pattern1 = 'afddsafsa';