kunnet

10 Scala One Liners to Impress Your Friends

Here are 10 one-liners which show the power of scala programming, impress your friends and woo women; ok, maybe not. However, these one liners are a good set of examples using functional programming and scala syntax you may not be familiar with. I feel there is no better way to learn than to see real examples.

Updated: June 17, 2011 - I'm amazed at the popularity of this post, glad everyone enjoyed it and to see it duplicated across so many languages. I've included some of the suggestions to shorten up some of my scala examples. Some I intentionally left longer as a way for explaining / understanding what the functions were doing, not necessarily to produce the shortest possible code; so I'll include both.

1. Multiple Each Item in a List by 2

The map function takes each element in the list and applies it to the corresponding function. In this example, we take each element and multiply it by 2. This will return a list of equivalent size, compare to o

	/*
	* Copyright (C) 2016 Jeff Gilfelt.
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software

	import redis.clients.jedis.Jedis;
	import redis.clients.jedis.PipelineBlock;

	/**
	* Author: Ashwin Jayaprakash
	* <p/>
	* Email: [email protected] Web: http://www.ashwinjayaprakash.com
	*/
	public class RedisJavaDemo {
	public static void main(String[] args) throws InterruptedException {

	# coding: utf8
	'''
	对于图片相似度比较有很多方法，我们这以RGB直方图为例。
	我们以一种规则，使得每个图片生成一组描述的特征向量。
	opencv的直方图比较函数我们可以巧妙的利用，其有若干比较规则，但只支持直方图的数据结构，我们可以将特征向量拟合成直方图的数据结构，然后使用其的相似度比较函数。
	具体的数学计算方法有兴趣的可以看opencv的官方教程，这里我们期望生成百分比形式的相似度参数，所以使用CV_COMP_CORREL

	以下是代码，以python编写
	'''
	import cv2.cv as cv

	class MyManagedResource extends ResourceController[String] {
	def index = Action(Ok("index"))

	def newScreen = Action(Ok("new"))

	def create = Action {
	Redirect(MyInjectableResource.reverseRoutes.index())
	}

	def show(id: String) = Action(Ok("Show " + id))

	# This config file was created for myself (@janlay). You may want to add or remove some rules to make efficient use of the Internet.

	# This file depends on the main.conf which defines your own proxy.
	# Your main.conf will look like this:
	# ---- START ----
	# #!PROXY-OVERRIDE:rules.conf
	# [Proxy]
	# Proxy = https,server.address,port,username,password
	# ---- END ----
	#


	from subprocess import Popen, PIPE
	from threading import Thread
	from Queue import Queue, Empty




	class CommandlineExecutor(object):
	STDERR = 0