QA Official

Java Operator and operator precedence Details: Including Results of i=i 2019-04-14
1. Arithmetic Operators 符 描述 例子 + 加法 - 相加运算符两侧的值 A + B 等于 30 - 减法 - 左操作数减去右操作数 A – B 等于 -10 * 乘法 - 相乘操作符两侧的值 A * B等于200 / 除

R language uses bagging method to classify and cross-verify data 2019-04-14
Data Classification Description R adabag package supports bagging and boosting, of which Bootstrap aggregating's Adabag package provides Breiman Bootstrap aggregating. The concept of sub-multi-version classifier is first proposed in Breiman bagging, and an aggregate classifier is obtained. operating data classification Import and Install Algorithm Package library(rpart) library(adabag) Call bagging function to complete the training of data set (different results may be produced in the training process) set.seed(2) churn.bagging = bagging(churn ~ .

VMware Virtual Machine Filename extension Details 2019-04-14
File management of virtual machines is performed by VMware workstation. A virtual machine is generally stored in the host in the form of a series of files, which are generally in the directory created by Workstation for virtual machines.The extensions of these key files are listed here.In these examples, < vmname > represents your virtual machine name..log < vmname >. log or VMware. log this file records the adjustment and operation of VMware Workstation to virtual machines.

VirtualBox Learning (II)-Virtual Storage-Continued 2019-04-14
virtual storage this is not finished, continue:   1. Write mode of hard disk image file: There are 6 write modes of virtual hard disk image file: 1) Normal mode, default mode.There are no restrictions on how virtual machines can read and write virtual hard disk image files. 2) writethroughharddisks mode.Compared with the normal mode, in this mode, when a snapshot is taken for a virtual machine, the state information is not saved in the snapshot.

Zookeeper Has Faded Brain Fissure in Distributed Environment 2019-04-14
Introduction to ZooKeeper I didn't know there was such a thing before I went to work. Before I started to talk about fake death and brain crack, let's talk about Zookeeper. ZookeeperZookeeper is a coordination service for distributed applications.It is a software that provides consistent services for distributed applications. Its performance includes configuration maintenance, name service, distributed synchronization, group service, etc.Zookeeper is based on Fast paxos (computer science), and Paxos (computer science) has livelock's problem, that is, when multiple proposers are submitted in a staggered way, they may mutually exclude each other, resulting in no proposer being submitted successfully.

downtime.js。Countdown JQ Plug-in 2019-04-14
downtime.js /*! * jQuery downtime plugin * version 0.2 * Author: Rob Griffiths <[email protected]> * Licence: MIT license */ /* * Copyright (c) 2012 Rob Griffiths * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify,

flex Optimization Complete Set 2019-04-14
1、当创建一个数组的时候避免用new操作符用 var a:Array = [];而不用var a:Array = new Array();2、传统的这样来简历数组的话代价是非常昂贵的:va

jQuery Countdown Settings Properties such as Days, Hours, Minutes, Seconds Only Need to Modify Expiration Time -20130724 2019-04-14
1、效果及功能说明 通过对时间的控制来告诉用户一个活动还剩多少时间,精确到秒2、实现原理 首先定义活动的截至的时间,要重年份精确到毫秒,在获得当

jquery Sends Mobile Phone Verification Code Countdown Plug-in Supports Page Refresh 2019-04-14
In the latest project, we need to use SMS Verification Code to send short messages. After searching the Internet for half a day, we couldn't find a satisfactory one, so we wrote one ourselves. jquery's packaged countdown plug-in for sending mobile phone verification codes uses cookie to prevent page refresh. 实现思路: 1.实现点击按钮,对手机号进行

pip virtualenv requirements 2019-04-14
pip can easily install, uninstall and manage Python packages. virtualenv can establish multiple independent virtual environments, each with its own python interpreter and its own package package, which do not affect each other. pip and virtualenv can work together well, and it is very convenient to use both tools at the same time.pip is usually installed first. After installation, pip install virtualenvcan automatically download and install virtualenv from the internet.