<?xml version="1.0" encoding="utf-8" ?><rss version="2.0"><channel><title><![CDATA[]]></title><description><![CDATA[]]></description><link>https://blog.youkuaiyun.com/anpan7274</link><language>zh-cn</language><generator>https://blog.youkuaiyun.com/</generator><copyright><![CDATA[Copyright &copy; anpan7274]]></copyright><item><title><![CDATA[决策树]]></title><link>https://blog.youkuaiyun.com/anpan7274/article/details/101127634</link><guid>https://blog.youkuaiyun.com/anpan7274/article/details/101127634</guid><author>anpan7274</author><pubDate>Mon, 10 Apr 2017 12:43:00 +0800</pubDate><description><![CDATA[￼

熵

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条件熵

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经验熵 经验条件熵

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相对熵 互信息

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决策树 (Decision Tree)

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ID3 信息增益 （容易过拟合）

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计算信息增益

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选择信息增益最大的特征作为当前的分裂特征
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例子

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C4.5 信息增益比

以信息增益 作为划分训练...]]></description><category></category></item><item><title><![CDATA[python基础2 -画图]]></title><link>https://blog.youkuaiyun.com/anpan7274/article/details/101127638</link><guid>https://blog.youkuaiyun.com/anpan7274/article/details/101127638</guid><author>anpan7274</author><pubDate>Sun, 09 Apr 2017 14:05:00 +0800</pubDate><description><![CDATA[￼

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# Created by xuehz on 2017/4/9
import numpy as np
import matplotlib as mpl
import matplotlib.pyplot as plt
from scipy.stats import norm, poisson
i...]]></description><category></category></item><item><title><![CDATA[python基础1]]></title><link>https://blog.youkuaiyun.com/anpan7274/article/details/101127631</link><guid>https://blog.youkuaiyun.com/anpan7274/article/details/101127631</guid><author>anpan7274</author><pubDate>Sun, 09 Apr 2017 12:36:00 +0800</pubDate><description><![CDATA[Numpy提供了ndarray
arange/linspace/logspace
整数/布尔数组存取
二维数组的切片
元素去重
stack and axis
链接两个narange


#!/usr/bin/env python
# -*- coding: utf-8 -*-
# Created by xuehz on 2017/3/28
import numpy as np

if ...]]></description><category></category></item><item><title><![CDATA[如何实现用户的历史记录功能(最多n条)]]></title><link>https://blog.youkuaiyun.com/anpan7274/article/details/101127630</link><guid>https://blog.youkuaiyun.com/anpan7274/article/details/101127630</guid><author>anpan7274</author><pubDate>Sat, 08 Apr 2017 14:41:00 +0800</pubDate><description><![CDATA[￼
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转载于:https://www.cnblogs.com/xuehaozhe/p/ru-he-shi-xian-yong-hu-de-li-shi-ji-lu-gong-neng-z.html]]></description><category></category></item><item><title><![CDATA[如何让字典保持有序]]></title><link>https://blog.youkuaiyun.com/anpan7274/article/details/101127644</link><guid>https://blog.youkuaiyun.com/anpan7274/article/details/101127644</guid><author>anpan7274</author><pubDate>Sat, 08 Apr 2017 14:27:00 +0800</pubDate><description><![CDATA[￼


python 默认字典 不具有 有序性
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使用有序字典

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转载于:https://www.cnblogs.com/xuehaozhe/p/ru-he-rang-zi-dian-bao-chi-you-xu.html]]></description><category></category></item><item><title><![CDATA[如何快速找到多个字典中的公共键(key)]]></title><link>https://blog.youkuaiyun.com/anpan7274/article/details/101127628</link><guid>https://blog.youkuaiyun.com/anpan7274/article/details/101127628</guid><author>anpan7274</author><pubDate>Sat, 08 Apr 2017 14:14:00 +0800</pubDate><description><![CDATA[￼

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普通方法

每轮都有进球的球员（公共键）
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方法1

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转载于:https://www.cnblogs.com/xuehaozhe/p/ru-he-kuai-su-zhao-dao-duo-ge-zi-dian-zhong-de-gon.html...]]></description><category></category></item><item><title><![CDATA[如何根据字典中值的大小, 对字典中的项排序]]></title><link>https://blog.youkuaiyun.com/anpan7274/article/details/101127642</link><guid>https://blog.youkuaiyun.com/anpan7274/article/details/101127642</guid><author>anpan7274</author><pubDate>Fri, 07 Apr 2017 22:46:00 +0800</pubDate><description><![CDATA[￼
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方法1

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方法2

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转载于:https://www.cnblogs.com/xuehaozhe/p/ru-he-gen-ju-zi-dian-zhong-zhi-de-da-xiao-dui-zi-d.html]]></description><category></category></item><item><title><![CDATA[如何统计序列中元素的出现频度]]></title><link>https://blog.youkuaiyun.com/anpan7274/article/details/101127640</link><guid>https://blog.youkuaiyun.com/anpan7274/article/details/101127640</guid><author>anpan7274</author><pubDate>Fri, 07 Apr 2017 21:45:00 +0800</pubDate><description><![CDATA[￼

普通方法

from random import randint
data = [randint(0,20) for _ in xrange(30)]

c = dict.fromkeys(data,0) #0 为初始值

for x in data:
    c[x] + =1
sorted(c.iteritems(), key=lambda x: x[1], reverse=T...]]></description><category></category></item><item><title><![CDATA[如何为元组中的每个元素命名, 提高程序可读性]]></title><link>https://blog.youkuaiyun.com/anpan7274/article/details/101127639</link><guid>https://blog.youkuaiyun.com/anpan7274/article/details/101127639</guid><author>anpan7274</author><pubDate>Fri, 07 Apr 2017 15:02:00 +0800</pubDate><description><![CDATA[￼

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方法

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转载于:https://www.cnblogs.com/xuehaozhe/p/ru-he-wei-yuan-zu-zhong-de-mei-ge-yuan-su-ming-min.html]]></description><category></category></item><item><title><![CDATA[如何在列表, 字典, 集合中根据条件筛选数据]]></title><link>https://blog.youkuaiyun.com/anpan7274/article/details/101127626</link><guid>https://blog.youkuaiyun.com/anpan7274/article/details/101127626</guid><author>anpan7274</author><pubDate>Fri, 07 Apr 2017 14:53:00 +0800</pubDate><description><![CDATA[￼

解决办法：

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列表 方法1

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列表解析 方法2

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字典解析

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集合解析

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转载于:https://www.cnblogs.com/xuehaozhe/p/ru-he-zai-lie-biao-zi-dian-ji-he-zhong-gen-ju-tiao.html...]]></description><category></category></item><item><title><![CDATA[如何去掉字符串中不需要的字符]]></title><link>https://blog.youkuaiyun.com/anpan7274/article/details/101128227</link><guid>https://blog.youkuaiyun.com/anpan7274/article/details/101128227</guid><author>anpan7274</author><pubDate>Fri, 31 Mar 2017 20:32:00 +0800</pubDate><description><![CDATA[￼

方法1

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方法2

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方法3

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改进版本

（因为上面的方法只能替换一个符号）
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方法4

两种 translate()方法
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string下的translate()

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转变 a &gt; x b &gt; y c &gt; z


构建映射表

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结果

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上述 table 若为None 说明不做任何的映射 第二个参数 表示 要删...]]></description><category></category></item><item><title><![CDATA[如何对字符串进行左, 右, 居中对齐]]></title><link>https://blog.youkuaiyun.com/anpan7274/article/details/101128228</link><guid>https://blog.youkuaiyun.com/anpan7274/article/details/101128228</guid><author>anpan7274</author><pubDate>Fri, 31 Mar 2017 19:40:00 +0800</pubDate><description><![CDATA[￼

方法1

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方法2

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问题解决方法

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转载于:https://www.cnblogs.com/xuehaozhe/p/ru-he-dui-zi-fu-chuan-jin-xing-zuo-you-ju-zhong-du.html]]></description><category></category></item><item><title><![CDATA[如何将多个小字符串拼接成一个大的字符串]]></title><link>https://blog.youkuaiyun.com/anpan7274/article/details/101128253</link><guid>https://blog.youkuaiyun.com/anpan7274/article/details/101128253</guid><author>anpan7274</author><pubDate>Fri, 31 Mar 2017 10:17:00 +0800</pubDate><description><![CDATA[￼

方法1

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出现问题

资源浪费
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方法2

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若字符串中 有数字 可以使用 列表解析 
更完美的方法 是 使用生成器 （ ）
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转载于:https://www.cnblogs.com/xuehaozhe/p/ru-he-jiang-duo-ge-xiao-zi-fu-chuan-pin-jie-cheng-.html...]]></description><category></category></item><item><title><![CDATA[如何调整字符串中文本格式]]></title><link>https://blog.youkuaiyun.com/anpan7274/article/details/101128265</link><guid>https://blog.youkuaiyun.com/anpan7274/article/details/101128265</guid><author>anpan7274</author><pubDate>Thu, 30 Mar 2017 12:22:00 +0800</pubDate><description><![CDATA[￼

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方法 正则表达式 捕获组

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转载于:https://www.cnblogs.com/xuehaozhe/p/ru-he-diao-zheng-zi-fu-chuan-zhong-wen-ben-ge-shi.html]]></description><category></category></item><item><title><![CDATA[如何判断字符串a是否以字符串b开头或结尾]]></title><link>https://blog.youkuaiyun.com/anpan7274/article/details/101128252</link><guid>https://blog.youkuaiyun.com/anpan7274/article/details/101128252</guid><author>anpan7274</author><pubDate>Thu, 30 Mar 2017 12:06:00 +0800</pubDate><description><![CDATA[￼

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查看权限

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修改权限

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转载于:https://www.cnblogs.com/xuehaozhe/p/ru-he-pan-duan-zi-fu-chuana-shi-fou-yi-zi-fu-chuan.html]]></description><category></category></item><item><title><![CDATA[如何拆分含有多种分隔符的字符串]]></title><link>https://blog.youkuaiyun.com/anpan7274/article/details/101128263</link><guid>https://blog.youkuaiyun.com/anpan7274/article/details/101128263</guid><author>anpan7274</author><pubDate>Thu, 30 Mar 2017 11:52:00 +0800</pubDate><description><![CDATA[￼

In [6]: s
Out[6]: 'www       1227  0.0  0.0  15572  2096 pts/2    R+   10:29   0:00 ps aux'

In [8]: s.split?
Docstring:
S.split([sep [,maxsplit]]) -&gt; list of strings

Return a list of the ...]]></description><category></category></item><item><title><![CDATA[Pandas的时间序列处理]]></title><link>https://blog.youkuaiyun.com/anpan7274/article/details/101128229</link><guid>https://blog.youkuaiyun.com/anpan7274/article/details/101128229</guid><author>anpan7274</author><pubDate>Fri, 17 Mar 2017 19:53:00 +0800</pubDate><description><![CDATA[创建

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from datetime import datetime
import pandas as pd
import numpy as np

# 指定index为datetime的list
date_list = [datetime(2017, 2, 18), datetime(2017, 2, 19), 
             datetime(2017, 2, 25)...]]></description><category></category></item><item><title><![CDATA[偏差与方差]]></title><link>https://blog.youkuaiyun.com/anpan7274/article/details/101128230</link><guid>https://blog.youkuaiyun.com/anpan7274/article/details/101128230</guid><author>anpan7274</author><pubDate>Fri, 17 Mar 2017 16:02:00 +0800</pubDate><description><![CDATA[偏差-方差分解 试图对学习算法的 期望泛化错误率 进行分解。



测试样本 x
\(y_D\)为 x 在数据集中标记
y为x的真实标记
f(x;D)为训练集D上学得模型f 在x上的预测输出


学习算法的期望预测：
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偏差 方差 噪声 含义

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偏差：描述的是预测值（估计值）的期望与真实值之间的差距。偏差越大，越偏离真实数据，如下图第二行所示。

方差：描述的是预测值的...]]></description><category></category></item><item><title><![CDATA[可视化高峰数据]]></title><link>https://blog.youkuaiyun.com/anpan7274/article/details/101128261</link><guid>https://blog.youkuaiyun.com/anpan7274/article/details/101128261</guid><author>anpan7274</author><pubDate>Thu, 16 Mar 2017 23:45:00 +0800</pubDate><description><![CDATA[matplotlib 数据可视化
图像中文字体

数据集存在的问题


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#!/usr/bin/env python
# -*- coding: utf-8 -*-
# Created by xuehz on 2017/3/16

import pandas as pd
import matplotlib.pyplot as plt

from matplotlib impor...]]></description><category></category></item><item><title><![CDATA[数据可视化- bokeh]]></title><link>https://blog.youkuaiyun.com/anpan7274/article/details/101128248</link><guid>https://blog.youkuaiyun.com/anpan7274/article/details/101128248</guid><author>anpan7274</author><pubDate>Thu, 16 Mar 2017 19:30:00 +0800</pubDate><description><![CDATA[￼
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from bokeh.io import output_notebook, output_file, show
from bokeh.charts import Scatter, Bar, BoxPlot, Chord
from bokeh.layouts import row

import seaborn as sns

# 导入数据
exercise = sns.l...]]></description><category></category></item></channel></rss>