Doug's MATLAB Video Tutorials

January 8th, 2010

21:48 UTC | Posted in Format: Video, Level: Basic | Permalink | 3 Comments »

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3 Responses to “Basics: Refactoring a switchyard into a formula”

1. Han Geerligs replied on January 11th, 2010 at 10:45 UTC :
   

   Hi Doug,

   how about the behaviour of your function for input between a multiple of hundred and that value+1?
   As an example: the original code doesn’t assign a value to OutVal for val=100.5. Your refactored code assigns a value OutVal=100 to it.

   –Han

2. dhull replied on January 11th, 2010 at 18:28 UTC :
   

   Han,

   Good find! I do not know what the intentions of the original author were. I suspect that was an error in the original implementation, though we never discussed it. They may have also assumed integer input.

   Doug

3. Zane replied on January 13th, 2010 at 16:26 UTC :
   

   I remember coming up with this method for one of the ol’ Monday Math Madnesses. You can use floor(Val/100), etc to extract digits from a multidigit number after subtracting out higher orders. It’s not entirely refactoring because I didn’t find anyway to do it before, but uses a similar concept.

   Input=485;
   dig(1)=floor(Input/100);
   dig(2)=floor(Input/10)-dig(1)*10;
   dig(3)=floor(Input)-dig(1)*100-dig(2)*10;
   

   careful indexing could be applied to scale for much larger numbers.

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<pre class="code">
a = magic(3);
sum(a)
</pre>

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