Bash alphanumeric list generating

Question

I need print something like this:

a
b
c
.
.
.
z
A
B
C
.
.
.
Z
0
1
2
.
.
.
9

with this is can be done for separately but.

 for f in {a..z}; 
   do        
   echo $f;   
done
 for f in {A..Z}; 
   do        
   echo $f;   
done

 for f in {0..9}; 
   do        
   echo $f;   
done

but how can i do it in one for? Maybe something like this ? But is not working.

 for f in {a..z:A..Z:1..9}; 
   do        
   echo $f;   
done

Answer 1

for f in {a..z} {A..Z} {0..9}; do
    echo "$f"
done