One of the easiest places to delve into a new programming language I've always found to be string manipulation. Not one of the most exciting aspects of most modern programming languages. However so many atomic processes either boil down to manipulating strings or rely on it at one level or another. Now in clojure as with lisp before it due to the fact that all data is code and all code is also data, clojure does not explicitly provide functions to manipulate strings. Clojure's lazy evaluation means that all functions are data type agnostic, which takes some real getting used to coming from such strongly typed languages such as Java or C#. Meaning that even though these examples use strings they work with any type of collection: sets, lists, etc. Here are some examples of some basic data transformations you can do with clojure:
01. First function example
(first "test") = t
Return the first item in the collection.
02. Rest function example
(rest "test") = (e s t)
Return all the items in the collection except the first element.
03. Str function example
(str "test") = test
Return the items in the collection as a string. If there is more than 1 item they are concatinated together, if a single item is passed then str is equivalent to the java toString() method.
04. Set function example
(set "test") = #{e s t}
Return a set of the distinct items in the collection.
05. Subs function example
(subs "test" 1) = est
Return a subset of the collection from the start or designated starting point (0 based) to either the collection's end or the designated ending point.
06. Nth function example
(nth "test" 1) = e
Return the nth item in the collection.
07. Reverse function example
(reverse "test") = (t s e t)
Return a collection with the original collection's items in reverse order.
08. Drop function example
(drop 2 "test") = (s t)
Returns a collection of all but the first n item in the collection.
09. Drop-last function example
(drop-last "test") = (t e s)
Drop last item in collection.
10. Count function example
(count "test") = 4
Return the size of the collection.
11. Cons function example
(cons "test" "01") = (test 0 1)
Cons function from lisp. Constructs a new collection with "test" as the first item in the final collection and treats "01" as a collection separating its elements.
12. Concat function example
(concat "test" "01") = (t e s t 0 1)
Returns a lazy sequence representing the concatenation of the first collection's elements with the elements of the second collection.
13. Lazy-cat function example
(lazy-cat "test" "01") = (t e s t 0 1)
Returns a lazy sequence of the supplied collections.
14. Take function example
(take 2 "test" = (t e)
Returns the first n items in the supplied collection.
15. Take-last function example
(take-last 2 "test" = (t e)
Returns the last n items in the supplied collection.
16. Take-nth function example
(take-nth 2 "test" = (t s)
Returns every nth item in the supplied collection.
See the clojure 1.3 api for full specifications: http://clojure.github.com/clojure/
