Matlab Switch-case

matlab, switch-statement

Solution

`isnum` is not a Matlab function. `isnumeric` may be what you were thinking of, but it isn't what you typed. Which means your code is seeing `case isnum` and it has no idea what the heck `isnum` is, so it is telling you whatever it is, if you want to use it there you need to make it something that evaluates to a number (what it means by scalar) or to a piece of text (what it means by string constant).

Further, `ischar` is a matlab function, but you are not using it the right way. You must use it as `ischar(cA(x))` for example, will then evaluate to `true` if `cA(x)` is a string or snippet of text, will evaluate to `false` if `cA(x)` is anything else.

While it would be lovely if `switch` worked this way, it doesn't. You can't put a thing in the `switch` part, and then just list functions that need to be evaluated on that thing in the `switch` part.

The kind of thing you can do is this:

switch class(x)
    case 'double'
        fprintf('Double\n');
    case 'logical'
        fprintf('Logical\n');
end

Here I have used the `class` function the way it needs to be used, with an argument in it. And I then switch my cases based on the output of that function, class outputs a string.

Problem

I'm trying to write a function that puts the class, length, and value of each of the things in a cell array into a struct, but I keep getting an error with the switch statements ``` function [ out, common ] = IDcell( cA ) %UNTITLED Summary of this function goes here % Detailed explanation goes here cl={}; val={}; len={}; for x=1:length(cA) switch cA(x) case isnum cl(x)='double'; case ischar cl(x)='char'; case islogical cl(x)='logical'; case iscell cl(x)= 'cell'; end val=[val cA{x}]; len=[len size(value(x))]; end out=struct('value', val, 'class', cl, 'length', len); end [out]=IDcell(cA) SWITCH expression must be a scalar or string constant. Error in IDcell (line 8) switch cA(x) ```

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