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Searching for an element in a given list: `locate'
The abstraction `locate' returns the value `true' if the given list
contains an element fulfilling the condition defined by the predicate
function.
The abstraction `locatex' difers from `locate' only by returning the
element found in the list instead of `true' if it was found.
![\begin{lstlisting}[language=Scm]{}
(define locate (lambda(pred l)
(if (nullp l)...
... false
(if (pred (car l))
(car l)
(locatex pred (cdr l))))))
\end{lstlisting}](img134.gif)
![\begin{lstlisting}[language=Scm]{}
(define l1 (cons one
(cons two
(cons thre...
...rue
(bdisp! (locate (lambda(x) (equaln x five)) l1))
--> false
\end{lstlisting}](img135.gif)
Georg P. Loczewski
2004-03-05