mkaz

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

chenshuo

// answer to http://weibo.com/1915548291/z2UtyzuvQ
// see also http://www.cnblogs.com/baiyanhuang/archive/2012/11/11/2764914.html

#include <boost/bind.hpp>
#include <boost/function.hpp>
#include <boost/noncopyable.hpp>
#include <boost/ptr_container/ptr_vector.hpp>

#include <fstream>
#include <iostream>

liweinan

#对non-lock queue的简单分析#

今天看到 @梁斌penny 在打擂：http://coderpk.com

内容如下：

游戏规则： 比赛由pennyliang，就是本人梁斌同志坐庄，我提交baseline代码（可执行程序），和部分代码，方便统一游戏规则。 10亿数据（每个数据看作一个同志），1个队列，10个线程push，10个线程pop,走完一遍，考察总耗时，耗时最短的获胜。我的代码在我自己机器10亿数据排队进出,耗时1分28秒，内存峰值256MB（CPU16核，真8核那种，Intel(R) Xeon(R) CPU E5540 @ 2.53GHz）

packbase

L1 cache reference                          0.5 ns
Branch mispredict                             5 ns
L2 cache reference                            7 ns
Mutex lock/unlock                            25 ns
Main memory reference                       100 ns
Compress 1K bytes with Zippy              3,000 ns
Send 2K bytes over 1 Gbps network        20,000 ns
Read 1 MB sequentially from memory      250,000 ns
Round trip within same datacenter       500,000 ns
Disk seek                            10,000,000 ns