how can I break up a number into its separate digits

how can I break up a number say ABCD into its components, A, B , C and D?

Would I use floor, ceil, or fix? or maybe another command?

[Stephen23]

The MATLAB approach:

num = 5432

num = 5432

dgt  = num2str(num)-'0'

dgt = 1×4

5 4 3 2

[DGM]

I knew I was going to kick myself for not remembering that. It's like I can predict the future or something.

Answer 1

[DGM]

I'm sure I've seen more elegant ways, but off the top of my head, I don't remember. EDIT: ... oh.

I'm assuming we're talking about integers. You'll have to decide how you want to handle negative numbers. If you want the outputs to carry the sign of the input, you can do that:

a = -123456;

% a fairly straightforward way using text
b1 = sign(a)*str2double(num2cell(num2str(abs(a)).')).'

b1 = 1×6

-1 -2 -3 -4 -5 -6

% Stephen's comment above with sign-handling 
b2 = num2str(a)-'0';
b2 = sign(a)*b2(b2~=-3)

b2 = 1×6

-1 -2 -3 -4 -5 -6

% a mathematical approach is instructive, and can be done with a loop
ndigits = max(floor(log10(abs(a)))+1,1);
b3 = zeros(1,ndigits);
aa = a;
for d = ndigits:-1:1
    b3(d) = rem(aa,10);
    aa = fix(aa/10);
end
b3

b3 = 1×6

-1 -2 -3 -4 -5 -6

% but even then, the loop isn't necessary
b4 = rem(fix(a./10.^(fix(log10(abs(a))):-1:0)),10)

b4 = 1×6

-1 -2 -3 -4 -5 -6

[Michael]

thank you so much. I was thinking of doing something like say because its only 4 digits I am concerned about

doing something like

ones_digit=mod(number/1000);

tens_digit=mod(number/100);

hundreds_digit=mod(number/10);

thousdands_digit=mod(number/1);

or something like that? would I have to use floor to with that?Does what I have make any sort of sense?

[DGM]

What you have there is conceptually similar to the loop example. The behavior of mod() and rem() differ when considering negative numbers. Similarly, floor() and fix() differ when considering negative numbers. For positive integers, they would've been the same.

In practice, you'd want to avoid having separate named variables for each output, and generally you have no assurances of how many digits there will be. Using the loop and storing the output in a vector takes care of that. If you're only going to extract a certain handful of digits, then you might decide to define ndigits as a constant. That said, you would still probably want to make sure there are at least that many digits in the number.

[Michael]

Thank you.

I was told to have multiple outputs so that is why I used them. We haven't learned very many commands. Fix, floor, ceil, mod. And the basic operators.