Entries Tagged 'Clojure' ↓

In need of a quick program to force myself to dive in to clojure, I chose to implement a soundex program that I at one time had written in C++. It was a fun exercise to step back and look at how my thought process changed based on the language I used. Hope you find this useful.

;steps
;1 keep first letter
;2 replace consonants
;3 remove w and h
;4 two adjacent are same, letters with h or w separating are also the same
;5 remove vowels
;6 continue until 1 letter 3 nums

(use 'clojure.contrib.str-utils)

(defn trnsfrm[ word]
  (->>
    (re-gsub #"(?i)[fbvp]" "1" word)
    (re-gsub #"(?i)[cgjkqsxz]" "2" ,,) 
    (re-gsub #"(?i)[dt]" "3" ,,) 
    (re-gsub #"(?i)[l]" "4" ,,)
    (re-gsub #"(?i)[mn]" "5" ,,)
    (re-gsub #"(?i)[r]" "6" ,,)))

(defn replace-adjacent [word] 
  (->> (re-gsub  #"(?i)[wh]" "" word ) 
  	trnsfrm 
  	(re-gsub #"(?i)([a-z0-9])\1+" "$1" )))  	

(defn pad [word](subs (str word "0000") 0 4))  	

(defn do-soundex [word]
    (pad ( str (first word)(re-gsub #"[aeiouy]"  "" (subs (replace-adjacent word) 1)))))

Update Refactored version
Not quite happy with the above example, I decided to see if I could refactor my code. Below is what I came up with(4 less lines code).

(use 'clojure.contrib.str-utils)

(def re-map{ #"(?i)[fbvp]" "1",#"(?i)[cgjkqsxz]" "2",#"(?i)[dt]" "3",#"(?i)[l]" "4",#"(?i)[mn]" "5",#"(?i)[r]" "6" })

(defn trns [word] (map #(re-gsub (key %1) (val %1) word) re-map))

(defn pad [word](subs (str word "0000") 0 4))

(defn rm1 [word] (apply str(drop 1 word)))

(defn do-soundex [word]
    (pad(str (first word) (->>
        (re-gsub #"(?i)[^aeiou\d]" "" (apply str (apply interleave (trns word ))))
        (re-gsub #"(?i)([a-z\d])\1+" "$1" )
        rm1
        (re-gsub #"(?i)[a-z]" "" )))))

Now for the test cases

;;;Start test
(=(do-soundex  "Ashcroft") "A261")
(=(do-soundex  "Ashcraft") "A261")
(=(do-soundex  "Tymczak") "T522")
(=(do-soundex  "Pfister") "P236")
(=(do-soundex"lukaskiewicz")"l222")
(=(do-soundex"Rubin")"R150")
(=(do-soundex"Rupert")"R163")
(=(do-soundex"Robert")"R163")
(=(do-soundex "Vazquez")"V220")

;;;end test

I recently had the need to access gmail using Clojure. I used JavaMail to accomplish this via pop3. Below is some code that I wrote to help me get emails. Hope you find it useful Enjoy


(use '[clojure.contrib.duck-streams])
(def props (System/getProperties))
; Get the default Session object.
(def session (javax.mail.Session/getDefaultInstance props))

; send the email
(def transport (. session getTransport))
(. transport connect "smtp.gmail.com" 465 "sender@gmail.com" "password")
(. transport sendMessage msg (. msg getRecipients javax.mail.Message$RecipientType/TO))
(. transport close)


After the briefest of introductions to functional programming in college(a la Lisp) and dabbling with Scala, I took the functional plunge and started using Clojure recently. At this point, I have only written a couple of small programs and haven’t formed much of an opinion on where it stacks against my current favorite language at the moment(Groovy). This post will follow my usual getting started with a language snippets. I plan to write more entries as I get more familiar with the language. On to the code!

—
;binding
user=> (def Bonjour-Clojure “Welcome to functional programming”)
#’user/Bonjour-Clojure
user=> Bonjour-Clojure
“Welcome to functional programming”

;items in a list can be seperated via a comma or white space..
user=> (= [ 1 2 3] [1,2,3])
true

;count the number of consonants in a string
(defn count-consonants [string] (count ( re-seq #”[^aeiouAEIOU\s]” string )))
user=> (count-consonants “writing code is fun”)
10

;count the number of vowels in a string
(defn count-vowels [string] (count ( re-seq #”[aeiouAEIOU\s]” string )))
user=> (count-vowels “lukaskiewicz”)
5

;read a file into a list.. any suggestions on other ways are welcome
;usage (file-lines “string_path_to_file”) or to read a webpage ((file-lines “http://javazquez.com”)
(defn file-lines [file] (with-open [rdr (clojure.java.io/reader file)] ( set ( line-seq rdr))))

;view objects class
user=>(class “Im a string”)
java.lang.String

;length of string
user=>(count “I am 18 chars long”)
18

user=>(range 1 9)
(1 2 3 4 5 6 7 8 )

;repeat a digit
user=>(repeat 4 3)
(3 3 3 3)

;list comprehension
user=>(for [fruit ["apple" "orange" "grape"] ] (str fruit))
(“apple” “orange” “grape”)

;use map to create a new list… #() is a shortcut for an anonymous
user=>(map #(* 2 %1) [1 2 3 4])
(2 4 6 8 )

; also an anonymous function
user=> (map (fn [item](* 2 item)) [1 2 3 4])
(2 4 6 8 )

;simple fiter example on a list using odd?
user=> (filter odd? [1, 2,3,4,5])
(1 3 5)

;factorial using reduce
user=> (reduce * [1 2 3])
6

;if statement
user=> (if true (str “i am true”)(str “i am false”))
“i am true”