Dict-Set!

(dict-set! dictionary key value) -> #f

Destructively sets key to value in dictionary.

Example:

>>(define a (dict '(alpha 1) '(beta 2) '(gamma 3)))
:: #f
>>(dict-set! a 'alpha 9)
:: #f
>>a
:: [dict (gamma 3) (beta 2) (alpha . 9)]