Switch Case where case is a word_anynumber

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I am trying to make a switch case where the case is satisfied by the following:
word_anynumber (ie word_1 or word_2 etc)
what do i do to achieve this?
The issue is that i want the case to do the same thing for any case with word_#, but i don't want to create cases for each number because i have a variable number of numbers each time this script runs.
Any help would be greatly appreciated.
-Jonathan

Accepted Answer

Daniel Shub
Daniel Shub on 15 Nov 2011
A regular expression might be useful for this type of task. Using the following as the test case:
a = cellstr([repmat('word_', 100, 1), num2str((0:99)', '%02d')]);
b = cellstr([repmat('Word_', 100, 1), num2str((0:99)', '%02d')]);
c = cellstr([repmat('xword_', 100, 1), num2str((0:99)', '%02d')]);
x = [a;b;c];
The following:
~cellfun(@isempty, regexp(x, 'word_[0-99]', 'matchcase'));
will return true for any x that is word_# and fail on case changes. How to build your case/switch around this is not clear (it seems like an if/elseif/else problem to me.
  1 Comment
Jonathan Crider
Jonathan Crider on 15 Nov 2011
Thank you for your help. I ended up switching from a switch case to a if/elseif and used the regexp(x, 'word_[0-99]', 'matchcase') expression and it is working. This will be good for now, but i may revisit this later for speed reasons. Thank you all for your help.
-Jon

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More Answers (2)

Fangjun Jiang
Fangjun Jiang on 14 Nov 2011
Use strfind(), strcmp() or strmatch(). You may also consider use "if-else" rather than 'case-switch"
if strfind(StrVariable,'word_')
  1 Comment
Daniel Shub
Daniel Shub on 15 Nov 2011
I think this will evaluate to true if StrVariable is of the form * word_*. It doesn't require word to be the first element, numbers to follow the underscore, or the numbers to be the final elements.

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Jonathan
Jonathan on 14 Nov 2011
If all of your cases are similar to what you describe, then you can use strtok like this.
a = 'word_4';
b = 'word_27';
c = 'byte_3';
d = 'bit_14';
switchStr = a;
switch strtok(switchStr, '_')
case 'word'
disp('word')
case 'byte'
disp('byte')
case 'bit'
disp('bit')
otherwise
disp('otherwise')
end
This displays 'word'. Try repeating this with switchStr set to b, c, and d.
  6 Comments
Jonathan
Jonathan on 15 Nov 2011
a = 'apple';
b = 'orange';
c = 'banana';
d = 'grape_1';
e = 'grape_2';
f = 'grape_3';
switchStr = d; % goes through a through f
switch strtok(switchStr, '_')
case 'apple'
disp('apple')
case 'orange'
disp('orange')
case 'banana'
disp('banana')
case 'grape' % this is where i have a problem
disp('grapes')
end

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