Find words whose first and last three letters are equal: Difference between revisions

=={{header|Racket}}==

<lang racket>#lang racket

(define ((prefix-and-suffix-match? len) str)

(let ((l (string-length str)))

(and (>= l (* 2 len))

(string=? (substring str 0 len)

(substring str (- l len))))))

(module+ main

(filter (prefix-and-suffix-match? 3) (file->lines "../../data/unixdict.txt")))</lang>

{{out}}

<pre>'("antiperspirant" "calendrical" "einstein" "hotshot" "murmur" "oshkosh" "tartar" "testes")</pre>