#Factor, 118 113 bytes

This is an anonymous function.

[ >upper dup >array [ 1string 65 90 [a,b] [ 1string ] map dup reverse zip >hashtable at ] map "" join reverse = ] 

I don't know of a shorter way to generate an associative array of the alphabet :c

Factor, 118 113 bytes

This is an anonymous function.

[ >upper dup >array [ 1string 65 90 [a,b] [ 1string ] map dup reverse zip >hashtable at ] map "" join reverse = ] 

I don't know of a shorter way to generate an associative array of the alphabet :c

#Factor, 188 bytes

This is an anonymous function.

[ >upper dup >array [ 1string 65 90 [a,b] [ 1string ] map dup reverse zip H{ } clone-like at ] map "" join reverse = ] 

I don't know of a shorter way to generate an associative array of the alphabet :c

#Factor, 118 113 bytes

This is an anonymous function.

[ >upper dup >array [ 1string 65 90 [a,b] [ 1string ] map dup reverse zip >hashtable at ] map "" join reverse = ] 

I don't know of a shorter way to generate an associative array of the alphabet :c