MATLAB: Isn’t the function “isstrprop” not working properly for “alphnum” type argument

alphanumericisstrprop

I am trying to determine if an input is alphanumeric and I ran into this strange issue. For example, let's say I have the following:
userinput =
    28
K>> isstrprop(userinput, 'alphanum')
ans =
     0
However, when I change the userinput to 48, I get a different result:
userinput =
    48
K>> isstrprop(userinput, 'alphanum')
ans =
     1
My question is why does the isstrprop function considers 48 as an alphanumeric argument when it thinks 28 is not an alphanumeric argument? Thank you.

Best Answer

http://www.mathworks.com/help/matlab/ref/isstrprop.html
MATLAB classifies the elements of the str input according to the Unicode® definition of the specified category. If the numeric value of an element in the input array falls within the range that defines a Unicode character category, then this element is classified as being of that category.
28 is the ASCII FS (Field Separator) code, a meaning preserved in Unicode. FS is not alphanumeric.
48 is the ASCII code for '0', a meaning preserved in Unicode. '0' is an alphanumeric.
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