Is it possible to create an inline function which gives back n binary digits of a number in a vector?

The input parameters must be the number x itself, and the number of digits (N). So dec2base(x,2) is not good, because its output is a string, and because 0-s are truncated. So instead of '101' I need [1 0 1], and instead of '1' I need [0 0 1], if N = 3

Answer 1

[Walter Roberson]

Subtract '0' (the character for the digit 0) from dec2base or dec2bin

[Mr M.]

Sorry I don't understand

[Jos (10584)]

x = 1
n = 3
S = dec2bin(x,n) 
V = S - '0'

[Mr M.]

Yes I see, but I don't understand why this is good?

[Stephen23]

"Yes I see, but I don't understand why this is good?"

Because it gives you exactly what you asked for. Did you try it?

[Mr M.]

Yes, but I don't understand teh syntax: -'0'

[Stephen23]

Some character vector minus the character zero?

This just subtracts a scalar number from a vector. What is the problem with that?

Everything on your computer is stored as numbers: all of those nice colors, happy music, and (most importantly for you right now) all of the text characters. A MATLAB char array is therefore just an array of numbers, which normally get interpreted as some glyph when it is displayed (and of course we all know that how something is displayed and how something is stored in memory are two quite different things). Because that char vector is actually an array of numbers you can simply perform numeric operations on them. Most of the time this is rather meaningless, but sometimes it has some neat properties, such as the answer you were given to get the numeric digits from a string of digit characters.

You can get the character vector's numeric values using either of these:

double(S)
+S

and for the zero character:

double('0')
+'0'

And then the reason why this answer works is pretty obvious. You could have investigated this yourself without destroying your computer: did you know that experimenting with MATLAB is encouraged, and will help you to learn?

[Mr M.]

"did you know that experimenting with MATLAB is encouraged"

Yes, thanks! BUT in general, finding solutions on the forum could be important for others also

Answer 2

[Guillaume]

You can either use

V = dec2bin(x, N) - '0'

as per Walter's answer or

V = bitget(x, N:-1:1)

The advantage of the first version is that it works with non-scalar x (and gives you a 2d matrix). The advantage of the second method is that it probably is a bit faster for scalar inputs.