<?xml version="1.0" encoding="utf-8" ?><rss version="2.0"><channel><title><![CDATA[PompeiiMassacre]]></title><description><![CDATA[PompeiiMassacre]]></description><link>https://blog.youkuaiyun.com/yangjiongjohn</link><language>zh-cn</language><generator>https://blog.youkuaiyun.com/</generator><copyright><![CDATA[Copyright &copy; yangjiongjohn]]></copyright><item><title><![CDATA[Logistic Regression]]></title><link>https://blog.youkuaiyun.com/yangjiongjohn/article/details/80049335</link><guid>https://blog.youkuaiyun.com/yangjiongjohn/article/details/80049335</guid><author>yangjiongjohn</author><pubDate>Mon, 23 Apr 2018 13:34:24 +0800</pubDate><description><![CDATA[逻辑回归定义的代价函数为： 
J(θ)=1m∑i=1mCost(hθ(x(i)),y(i))J(θ)=1m∑i=1mCost(hθ(x(i)),y(i)) J(\theta)=\frac{1}{m}\sum\limits_{i=1}^mCost(h_\theta(x^{(i)}),y^{(i)}) 

为保证代价函数呈凸形曲线，将其 log 处理

Cost(hθ(x),y)={−log(hθ(x...]]></description><category></category></item><item><title><![CDATA[Machine Learning Overview]]></title><link>https://blog.youkuaiyun.com/yangjiongjohn/article/details/80049189</link><guid>https://blog.youkuaiyun.com/yangjiongjohn/article/details/80049189</guid><author>yangjiongjohn</author><pubDate>Mon, 23 Apr 2018 13:17:09 +0800</pubDate><description><![CDATA[什么是机器学习?有什么用?


机器学习是什么? 
以前已知方程和x,求y.机器学习是已知x和y,求方程.
有什么用? 
机器学习可以用来解决回归预测,分类,聚类等问题.
如何学习机器学习 
https://www.zhihu.com/question/51039416/ 普通程序员如何正确学习人工智能方向的知识？
CS229入门,可以辅助看看《Python机器学习》
进阶阶段可以在kaggle练...]]></description><category></category></item><item><title><![CDATA[Markdown test]]></title><link>https://blog.youkuaiyun.com/yangjiongjohn/article/details/45587633</link><guid>https://blog.youkuaiyun.com/yangjiongjohn/article/details/45587633</guid><author>yangjiongjohn</author><pubDate>Fri, 08 May 2015 23:39:02 +0800</pubDate><description><![CDATA[John’s Cmd Markdown Memo



备注


  
  标题带*的话,表示通用平台并不支持.可能引入那些 js 文件也可以.
  本平台可用来输入文档,临时移动端浏览等.最终知识还是要总结到项目中.
  导出功能需要付费!很多代码在其他平台无法用,对我来说还是算了吧.
  




Windows/Mac/Linux 全平台客户端


  请保留此份 Cmd Markdown ...]]></description><category></category></item><item><title><![CDATA[世豪，附件在本文中！！！]]></title><link>https://blog.youkuaiyun.com/yangjiongjohn/article/details/84705865</link><guid>https://blog.youkuaiyun.com/yangjiongjohn/article/details/84705865</guid><author>yangjiongjohn</author><pubDate>Wed, 11 Mar 2015 22:31:18 +0800</pubDate><description><![CDATA[
无内容。
]]></description><category></category></item><item><title><![CDATA[sql study conclusion]]></title><link>https://blog.youkuaiyun.com/yangjiongjohn/article/details/84687072</link><guid>https://blog.youkuaiyun.com/yangjiongjohn/article/details/84687072</guid><author>yangjiongjohn</author><pubDate>Thu, 20 Nov 2014 23:10:26 +0800</pubDate><description><![CDATA[
select as 之后，列名还是原来的。
 
index
view
join
 
SQL 教程
 
SQL SELECT DISTINCT
比如有两种国家，三个条目，那么返回的就是两个国家（if you “select distinct country from table_name&quot;）
SQL WHERE
select * from customers where c...]]></description><category></category></item><item><title><![CDATA[About thoughts]]></title><link>https://blog.youkuaiyun.com/yangjiongjohn/article/details/84687034</link><guid>https://blog.youkuaiyun.com/yangjiongjohn/article/details/84687034</guid><author>yangjiongjohn</author><pubDate>Thu, 20 Nov 2014 20:08:48 +0800</pubDate><description><![CDATA[
=Scenario One=
when you're at a mall
open chaps and gps
all the chapps will pop out about this mall
once you circle down the sub categories,like computer accessories
you will get more specific ...]]></description><category></category></item><item><title><![CDATA[python scrawler]]></title><link>https://blog.youkuaiyun.com/yangjiongjohn/article/details/84687003</link><guid>https://blog.youkuaiyun.com/yangjiongjohn/article/details/84687003</guid><author>yangjiongjohn</author><pubDate>Thu, 20 Nov 2014 17:23:15 +0800</pubDate><description><![CDATA[
__author__ = 'YJatt'

import urllib2

url=&quot;http://www.cnblogs.com/way_testlife/archive/2010/06/14/1758276.html&quot;

html=urllib2.urlopen(url,timeout=100).read()

print html
 actually,it's prett...]]></description><category></category></item><item><title><![CDATA[python input&raw_input]]></title><link>https://blog.youkuaiyun.com/yangjiongjohn/article/details/84686808</link><guid>https://blog.youkuaiyun.com/yangjiongjohn/article/details/84686808</guid><author>yangjiongjohn</author><pubDate>Thu, 20 Nov 2014 00:24:58 +0800</pubDate><description><![CDATA[
__author__ = 'YJatt'

# if both n1 and n2's inputs are 1+2,no quotation marks attached
n1 = input(&quot;this is a expression : &quot;)

n2 = raw_input(&quot;this is always a string : &quot;)

print n1
#print 3...]]></description><category></category></item><item><title><![CDATA[html5 TankBattle]]></title><link>https://blog.youkuaiyun.com/yangjiongjohn/article/details/84684716</link><guid>https://blog.youkuaiyun.com/yangjiongjohn/article/details/84684716</guid><author>yangjiongjohn</author><pubDate>Mon, 10 Nov 2014 13:51:50 +0800</pubDate><description><![CDATA[
&amp;lt;canvas id=&quot;tankMap&quot; width=&quot;400px&quot; height=&quot;300px&quot; style=&quot;background-color:black&quot;&amp;gt;&amp;lt;/canvas&amp;gt;
 
//得到画布
var canvas1=document.getElementById(&quot;tankMap&quot;);
//得到绘图上下文(你可以理解是画笔)
var ]]></description><category></category></item><item><title><![CDATA[Install Django]]></title><link>https://blog.youkuaiyun.com/yangjiongjohn/article/details/84684546</link><guid>https://blog.youkuaiyun.com/yangjiongjohn/article/details/84684546</guid><author>yangjiongjohn</author><pubDate>Sun, 09 Nov 2014 00:41:42 +0800</pubDate><description><![CDATA[
Using ubuntu [basic]
 
install python (come with os)
 
install Intellij Idea (gotta install jdk first)
 
install Django(install pip or easy_install first)
]]></description><category></category></item></channel></rss>