[plt-scheme] convert string to list

I am new to using Scheme. I am trying to convert a string to a list. It 
needs the list to be like '(55 34 rr = ) and not '(#\5 #\5 #\space #\3 #\4 
#\space #\r #\r #\space #\= ). Is there a simple way to get the list '(55 
34 rr =) from the string "55 34 rr =". Thanks for any help you have!

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