bcambel

Clojure Destructuring Tutorial and Cheat Sheet

(Related blog post)

Simply put, destructuring in Clojure is a way extract values from a datastructure and bind them to symbols, without having to explicitly traverse the datstructure. It allows for elegant and concise Clojure code.

Vectors

bcambel

(ns cascalog.conj.tunisia
  (:use [cascalog api playground])
  (:use [cascalog.contrib.incanter])
  (:use [cascalog.util :only [collectify]])
  (:use [clojure.contrib.def :only [defnk]])
  (:require [cascalog [ops :as c] [vars :as v]])
  (:require [clojure.data [json :as json]]))

(bootstrap-emacs)

bcambel

(ns aud_cas.print_fields
  (:use cascalog.api)
  (:require [clojure.string :as str])
  )

(defn parse_input_record
  "Parse the text of the input record into fields in a map"
  [input_record]
  (let [prefix_string (get (str/split input_record #"\: ") 0)
        prefix_pairs (str/split prefix_string #" ")

bcambel

(ns rbl.feature-extraction.user-agent
  (:use [clojure.core.memoize :only [memo]])
  (:require [clojure.tools.logging :as log])
  (:import [nl.bitwalker.useragentutils UserAgent DeviceType Browser OperatingSystem]))

(defn str->features [string]
  (try
    (let [user-agent (UserAgent. (or string ""))]
      {:browser_group (-> user-agent .getBrowser .getGroup .getName)
       :os_group (-> user-agent .getOperatingSystem .getGroup .getName)

bcambel

sudo apt-get install openjdk-7-jdk
java -version
# java version "1.7.0_25"
# OpenJDK Runtime Environment (IcedTea 2.3.12) (7u25-2.3.12-4ubuntu3)
# OpenJDK 64-Bit Server VM (build 23.7-b01, mixed mode)
cd /usr/lib/jvm
ln -s java-7-openjdk-amd64 jdk
 
sudo apt-get install openssh-server

bcambel

set -x LEIN_SNAPSHOTS_IN_RELEASE y
set -x DOCKER_HOST tcp://192.168.59.103:2376
set -x DOCKER_CERT_PATH /Users/bahadir/.boot2docker/certs/boot2docker-vm
set -x DOCKER_TLS_VERIFY 1
set -x LC_ALL en_US.UTF-8
set -x LANG en_US.UTF-8

alias tigs "tig status"
alias gitpatch "git add * -p"
alias gitpm "git push origin master"

bcambel

"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
" Maintainer: 
"       Amir Salihefendic
"       http://amix.dk - amix@amix.dk
"
" Version: 
"       5.0 - 29/05/12 15:43:36
"
" Blog_post: 
"       http://amix.dk/blog/post/19691#The-ultimate-Vim-configuration-on-Github

bcambel

(ns fetcher.core
(:use [clojure.java.io :as io])
(:use [net.cgrand.enlive-html]))

(defn fetch-all-images-from-url [src-url dest-folder]
      (let [
            ; get root from src-url: http://google.com/alias1/2/3 ---> http://google.com
            root-url (clojure.string/join "/" (take 3 (clojure.string/split src-url #"/")))

            ; function: if image url starts with "/" ( / character is: \/ in Clojure, ex \a \b etc...) append root url

bcambel

;; all the following destructuring forms can be used in any of the 
;; Clojure's `let` derived bindings such as function's parameters,
;; `let`, `loop`, `binding`, `for`, `doseq`, etc.

;; list, vectors and sequences
[zero _ _ three & four-and-more :as numbers] (range)
;; zero = 0, three = 3, four-and-more = (4 5 6 7 ...),
;; numbers = (0 1 2 3 4 5 6 7 ...)

;; maps and sets

bcambel

"""
=========================================================
Comparing different clustering algorithms on toy datasets
=========================================================

This example aims at showing characteristics of different
clustering algorithms on datasets that are "interesting"
but still in 2D. The last dataset is an example of a 'null'
situation for clustering: the data is homogeneous, and
there is no good clustering.