What's the canonical way to join strings in a list?

Question

I want to convert (\"USERID=XYZ\" \"USERPWD=123\") to \"USERID=XYZ&USERPWD=123\". I tried

(apply #\'concatenate \'string \'(\"         


        

Answer 1

A bit late to the party, but reduce works fine:

(reduce (lambda (acc x)
          (if (zerop (length acc))
              x
              (concatenate 'string acc "&" x)))
        (list "name=slappy" "friends=none" "eats=dogpoo")
        :initial-value "")