Switch Case where case is a word_anynumber

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

Answer 1

[Daniel Shub]

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.

[Jonathan Crider]

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

Answer 2

[Fangjun Jiang]

Use strfind(), strcmp() or strmatch(). You may also consider use "if-else" rather than 'case-switch"

if strfind(StrVariable,'word_')

[Daniel Shub]

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.

Answer 3

[Jonathan]

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.

[Jonathan Crider]

the setup to this problem is that i am doing a switch on a string and there are a number of cases each corresponding to a certain string. One of the cases is that of word_# where number can be anything. Hence, i don't think that the strtok will work in its use here.

something like this:

Jonathan answered 11 minutes ago

If all of your cases are similar to what you describe, then you can use strtok like this.

a = 'apple';

b = 'orange';

c = 'banana';

d = 'grape_1';

e = 'grape_2';

f = 'grape_3';

switchStr = a; % goes through a through f

switch 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

[bym]

how many numbers do you wish to distinguish? 1-10, 1-255,1-inf ?

[Jonathan Crider]

it will only be 2 digit numbers

[Jonathan Crider]

Let me clarify. No larger than 2 digit numbers.

[Jonathan]

strtok does work in this case since "strtok('apple', '_')" returns the string "apple".

[Jonathan]

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