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1. The centrality of dataThe so-called centralization of data refers to the data in the dataset minus the mean of the data set.For example, there are datasets 1, 2, 3, 6, 3, and its mean value is 3, then the data set after the 1-3,2-3,3-3,6-3,3-3 is a: -2,-1,0,3,02. Standardization of dataStandardization of the so-called data refers to the normalized data divided by the standard deviation of the dataset, that is, the data in the dataset minus the mean of the dataset, divided by the standard devi

R language is very convenient for numerical calculation, recently used in the calculation of variance, standard deviation of the function, special records.Data preparationHeight 1 Calculating the mean valuemean (height) [1] 5.8552 median of calculationsmedian (height) [1] 5.923 Calculating the standard deviationSD (height) [1] 0.18717194 Calculating Variancevar (height) [1] 0.035033335 Calculating the correlation coefficients between two variablesCor

Video lessons include:18 Palm Xu Peicheng Teacher Employment class full set of Big Data video 86G contains: Hadoop, Hive, Linux, Hbase, ZooKeeper, Pig, Sqoop, Flume, Kafka, Scala, Spark, R Language Foundation, Storm Foundation, Redis basics, projects, and more!2018 the most fire may be the number of big data, here to you according to a certain way to organize a full set of big Data video tutorials, covering big data all knowledge points.This video bel

Purpose of writingRecently, because of the research needs, the text has been subject to discovery using the R language, and the following is a record of the specific process.Step one: Read the text and preprocess itIn this experiment, we mainly analyze the index records of Bigdata from SCI Citation database, the file name is Download_2.txt directory c:\\data\\, the specific code is:#文件路径textfile Step two: Build a documenttermmatrix matrix using a TM P

Source: http://www.dataguru.cn/article-794-1.htmlThe Rugarch package is a package in R that is used to fit and test the GARCH model. The package was first published on Http://rgarch.r-forge.r-project.org and has now been published on Cran. In simple terms, the package consists of four functions: Fitting Garch Family Model Garch Family Model Diagnosis Garch Family Model Prediction Analog Garch Sequence Fitting sequence Distribu

Factor (factor) and ordered factor (ordered factor)Factors are used to store categorical variables (categorical variables) and ordered variables, which cannot be used to calculate but only to classify or count. Factors represent categorical variables, and ordered factors represent ordered variables.The function that generates the factor data object is factor (), the syntax is factor (data, levels, labels, ...), where data is the parameter, levels is the factor horizontal vector, and labels is th

After tossing the crawler and some interesting content, I recently in the R language for simple machine learning knowledge, the main reference is "machine learning-Practical Case Analysis" this book.This book is a rare, purely r language-based machine learning knowledge, covering 11 cases. Divided into 12 chapters. Both the author's notes and the code sections are quite deep. But perhaps because the book ea

in the R language, linear discriminant analysis (Liner discriminant analyses, or LDA) is implemented by using thelinear discriminant function Lqa () in the package mass. The function has three invocation formats:1) When the object is data.frame the data frameLDA (X,grouping,prior = Propotions,tol = 1.0E-4,METHOD,CV = False,nu,...)2) When the object is a formula formulaLDA (Formula,data,..., subnet,na.action)3) When the object is matrixLDA (X,group,...

Java escape character I always thought it was difficult to understand, I often confuse the \ symbol and/symbol, do not know that one is an escape character.In the Java language you want to know \ is a hate a person's species, \ always like Su-eun love, generally are in pairs appear like \ \, but there will be a small number of wonderful flowers do not like the other half \, they like other characters, these wonderful characters and human homosexuality is not the same as most people like, They li

First, find the fileUse the shortcut key "ctrl+shift+r" to pop up the pop-up file lookup box, as shown in:　　Second, find the file containing a stringUse the shortcut key "ctrl+h" in the pop-up dialog to select the File search option, and then paste in the first text box (I usually paste) or self-input (easy to write wrong) to find the string (can be English characters can also be Chinese characters), In the second text box, enter the file you want to

weather is set to Yin, wind after the wind are based on the day before and after. The following two figures are missing from the historical weather data found on two different websites.After cleaning up the data, save the CSV format, enter the data into R, and view the basic structure of the data as follows:Beijing Each column is: Date (date), highesttemp (maximum temperature), lowest (lowest temperature), weather (weather), wind (direction), WindFor

://www.baidu.com")HtmlRead DatabaseIf you need to connect to the database in R, mostly using ODBC to connect, you need to install package rodbc. If it is a Linux or Mac platform, you can install the Rmysql package for MySQL database. Because I'm a Mac now, for example, I've created a table employee in the MySQL test database, and now I need to read the table. Library (Rmysql)Conn"Test", host="127.0.0.1"Next we want to see what tables we have, which ca

Using the R language, draw two graphics in a drawing window, using the layout manager.1. The commands for drawing autocorrelation and partial autocorrelation graphs are:> par (pin=c (4,2), Mfrow=c (2,1)) #设置图形大小 (length 4 ", Height 2"), divided into 2 rows and 1 columns> Layout (Matrix (c (1,1,2,2), 2,2,byrow=true)) #将绘图区分成4个单元格, 1th, 2 is a row, 3rd, 4 is a row. > layout.show () #显示布局> ACF (C2) #自相关图> pacf (C2) #偏自相关图Draw as:2, only calculate not d

The use of simple functions of the R language:"C () is a connection function, the middle of the data representation of the vector, the connection between the middle of the data representation vector, X1 Mean () is the mean function, and mean (X1) represents the standard deviation of the computer array X1.SD () is the standard deviation function, and SD (X1) represents the standard deviation of the computer array X1.> x1+,max, Max,Max,PNs, (mean) > (X1

In the Linux system has been using the upper and lower keys to find the previous input commands, this find just entered the command is very convenient, but more distant command, with the upper and lower key efficiency is not high. The history command is also a showy, although the function is many, but does not use, the net looked under, discovered with the CTRL + R this shortcut key to find the historical order, studied the discovery really to be usef

default size. The default size is 1,1.5 to 1.5 times times the default value, 0.5 for the default value of 50%, and so on.LBL: Label labelC: Represents a Data collectionXlim,ylim: x, y coordinate range, for example:Ylim=c ( -40,40), Xlim=c (0,100)main: TitleSub: SubtitleXlab, Ylab: Axis labels3. Graphics boundariesThe graphic size (width and height) of the pin in inches. Memory Method: Picture inchmai The size of the boundary , expressed as a numeric vector, in the order of "bottom, left, top,

Tiobe released the November programming language rankings, the first three are still C, Java, Objective-c. Affected by Big data, the R language this month rose to 12, last month ranked 15th, watching its trend next month is expected to the top 10.Thanks to Big Data hype, some languages include Julia (#126), LabView (#63), Mathematica (#80), MATLAB (#24), S (#84), SAS (#21), SPSS (#104), and Sta TA (#110) share has risen.Top 20 List of programming lang

The format character is to reserve a location for the real value and to control the format of the display.A format character can contain a type code that controls the type of display, as follows:%s string (shown with STR ())%r string (shown with repr ())%c single character%b binary integers%d decimal integers%i Decimal Integer%o Eight-binary integers%x hexadecimal integer%e index (base written as E)%E index (base written as E)%f floating Point%F float

I am very interested in mathematics, suffering from the mathematical theorem formula to be afraid of life, have always wanted to use a simple, popular way to show the charm of mathematics, Learning R language for a period of time, feel can use this tool to verify some mathematical theorem, also is a kind of fun, say dry, first a simple pointLarge number theorem:In the large number of repeated occurrences of random events, it tends to show almost inevi

") #计算Nagelkerke拟合优度R2 =r2/(1-exp (-pre$null.deviance)/N) Cat ("Nagelkerke r2=", R2, "\ n") #Nagelkerke r2= 0.7379711 #模型其他指标 #residuals (PRE) #残差 #coefficients (PRE) #系数 #anova (pre) #方差　　4. Accuracy and precisionTRUE_VALUE=AUS_TEST[,15]PREDICT_VALUE=AUS_TEST[,16] #计算模型精度error =predict_value-true_value# to determine the proportion of the correct number in the total Accuracy= (Nrow (aus_test)-sum (ABS (Error)))/nrow (aus_test) #混淆矩阵中的量 (The confusion matrix is explained on the