Pattern matching problem

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

[Matt Fig]

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';

[B_Richardson]

According to HELP, it appears that STRFIND has to find an exact match between 2 strings? In my case im just looking for SHC, RHA, or SLR.

[Matt Fig]

That is not what the help says.

K = STRFIND(TEXT,PATTERN) returns the starting indices of any

occurrences of the string PATTERN in the string TEXT.

So if PATTERN appears at all in TEXT then you will get a number back. If not, you will get an empty array, which will not pass the IF statement.

[B_Richardson]

pattern1 = 'SHC\W';

pattern2 = 'SLR\W';

pattern3 = 'RHA\W';

indexselected = get(handles.listbox1,'Value');

list = get(handles.listbox1,'String');

itemselected = list{indexselected};

if STRFIND(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 STRFIND(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 STRFIND(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

%END%

Still produces no results. Is there something wrong with my regular expression?

[Matt Fig]

Does your itemselected have ALL of this in it: 'SHC\W'

The examples you gave did not have the \W so it is no wonder no matches are found. Did you see my example above?

[B_Richardson]

The full path to the video is:

C:\Users\ecorbett\Documents\VCoachData\0008_Capture_10152009\Video\RHA

[B_Richardson]

Actually, I think I was confused (as always) as to what the movieplayer function was sending to the listbox. It does look for the fullpath, but I now see that the contents in the box are:

SHC_LL_S1_0008_V5.5983338494.avi

So what regular expression would I need to match this pattern?

[Matt Fig]

Again, I would not use regular expressions. A simple match will work if you only have 3 patterns. Look at my example above. There is no need to use regular expressions when you know the exact match before hand.

[B_Richardson]

Nevermind Matt. I got it to work. something is wrong with my excel files now. But the pattern matching is working. Thanks a million!