Match numbers to allocate text

Hi,

I am struggling to match numbers to assign a corresponding string. For example,

I have an array

x=[A 12
    B 13
    C 19
    D 21]

and another array

 y= [12 13 19 24 21 12 12]

I would prefer to get

z=[12 A
    13 B
    19 C
    24 NaN
    21 D
    12 A
    12 A]

Any help is appreciated

Answer 1

[Karim]

you can use the categorical command to do this:

y = [12 13 19 24 21 12 12]';

B = categorical( y, [12 13 19 21], ["A" "B" "C" "D"] ) 

B = 7×1 categorical array
     A 
     B 
     C 
     <undefined> 
     D 
     A 
     A 

Answer 2

[David Hill]

Your could also use a sparse array or an array of nan.

x=[12 13 19 21];
y=[12 13 19 24 21 12 12];
X=nan(1,25);
X(x)='ABCD';
Y=char(X(y))

Y = 'ABC DAA'

x=[12 13 19 21];
y=[12 13 19 24 21 12 12];
X=sparse(1,25);
X(x)='ABCD';
Y=char(full(X(y)))

Y = 'ABC DAA'