• Java 调用R 方法


     

    JAVA 调用 R 语言

    1       简介

    R是统计计算的强大工具,而JAVA是做应用系统的主流语言,两者天然具有整合的需要。关于整合,一方面,R中可以创建JAVA对象调用JAVA方法,另一方面,JAVA中可以转换R的数据类型调用R的函数,互相取长补短。现在也有一个项目JGR,用JAVA做R的图形界面,可以实现高亮显示自动补全等,还能让JAVA和R互相调用。

    关于R中调用JAVA,我想主要是为了利用其面向对象的特性,毕竟R语言近来很致力于向面向对象发展,有个很好的项目rJava可以实现,在www.rforge.net/rJava上。R中调JAVA对我似乎意义不大,本文主要介绍JAVA中调用R。

     JAVA很适合开发应用系统,但是数学建模和计算能力非其所长,如果该系统需要进行大量的统计或者优化的计算,调用R是一种很好的方式。JAVA负责系统的构建,R用来做运算引擎,从而实现应用型和分析性相结合的系统。

     目前网上有两种方式使用java调用R。

    2       Rserve的方式

    2.1     介绍

    首先要介绍的是Rserve的方式,这是一个基于TCP/IP的服务器,通过二进制协议传输数据,可以提供远程连接,使得客户端语言能够调用R。目前Rserve作为一个package发布在CRAN上,可以直接使用install.packages("Rserve")进行安装。需要使用时在R控制台下加载该包,然后输入命令Rserve(),开启服务器,就可以供客户端调用。

    其客户端可以有多种,这里只介绍JAVA客户端。最早的客户端包是JRclient,在www.rosuda.org/Rserve上还可以下载到,但是现在该项目全部移到了www.rforge.net/Rserve,使用REngine作客户端(和JRI一致),在该网站下可以下载到REngine.jar和RserveEngine.jar两个文件。如果用eclipse开发的话,在工程属性中导入这两个外部的jar包,就可以正常使用了。

    首先建立一个新的连接,然后就可以使用eval之类的方法将R中的表达式传到服务器端,通过R求值后传回JAVA中REXP类型的变量,然后打印出来,整个过程非常简单。由于不需要对R进行初始化,因此速度会比较快。在其他系统下可以同时建立多个连接,但是在Windows下只允许同时打开一个连接,后续的连接都会共有相同的命名空间。官网上不建议在Windows下使用Rserve,因为会丧失很多性能,他们推荐可以考虑DCOM的方式。不过DCOM那个工程没有现成的jar包可用,其实如果是拿R做分析系统中的运算引擎,单连接够用了。

    2.2     操作步骤

    (一)   在R里下载“Rserve”包,并安装

    安装好后,

    运行如下命令启动“Rserver”

    > library(Rserve)

    > Rserve()

    Starting Rserve...

     "D:PROGRA~1RR-30~1.1libraryRservelibsi386Rserve.exe" 

    (二)   建立java工程,导入必要的包,写出测试用例

    目录结构如下(标红色的是需要的):

    Test.java 内容

    package com.rTest;

     

    import org.rosuda.REngine.REXP;

    import org.rosuda.REngine.Rserve.RConnection;

     

    public class Test {

        public static void main(String[] args) {

           try {

               RConnection c = new RConnection();

               REXP x = c.eval("R.version.string");

               System.out.println(x.asString());

           } catch (Exception e) {

                e.printStackTrace();

           }

        }

    }

    运行即可

    2.3     可能出现的错误

    2.3.1  Connection refused: connect

    org.rosuda.REngine.Rserve.RserveException: Cannot connect: Connection refused: connect

        at org.rosuda.REngine.Rserve.RConnection.<init>(RConnection.java:88)

        at org.rosuda.REngine.Rserve.RConnection.<init>(RConnection.java:60)

        at org.rosuda.REngine.Rserve.RConnection.<init>(RConnection.java:44)

        at com.rTest.Test.main(Test.java:9)

    这是由于“Rserve” 服务器没有启动起来的原因,试试在R内运行如下语句

    > library(Rserve)

    > Rserve()

    3       JRI 的方式

    3.1     介绍

    另一种方式是JRI,全名是Java/R Interface,这是一种完全不同的方式,通过调用R的动态链接库从而利用R中的函数等。目前该项目已经成了rJava的子项目,不再提供单独的JRI的版本。因此使用时简单地通过install.packages("rJava")安装rJava就行,在安装文件夹中,可以看到一个jri的子文件夹,里面有自带的例子可以用来测试。

    装好后要修改系统的环境变量,在PATH中添加%R_HOME%/bin和%R_HOME%/library/rJava/jri,注意R_HOME的路径要正确,重启系统使之生效。使用时同样在eclipse里导入外部的jar包(在www.rforge.net/rJava下载JRI.jar、REngine.jar和JRIEngine.jar这三个文件),在rJava包安装目录下的jri/examples里有现成的例子(rtest.java和rtest2.java),可以测试是否成功。

    3.2     操作步骤

    (一)   在R中下载安装“Rjava”包

    (二)   配置环境变量

    我自己的path如下:

    D:Program FilesJavajdk1.7.0_09in;D:Program FilesRR-3.0.1ini386;D:Program FilesRR-3.0.1library Javajri;D:Program FilesRR-3.0.1library Javajrii386

    (三)   建立java工程

    标红线的是必须的

    Rtest 和Rest2 都是Rjava例子里的

    package com.rTest;

    import java.io.*;

    import java.awt.Frame;

    import java.awt.FileDialog;

    import java.util.Enumeration;

    import org.rosuda.JRI.Rengine;

    import org.rosuda.JRI.REXP;

    import org.rosuda.JRI.RList;

    import org.rosuda.JRI.RVector;

    import org.rosuda.JRI.RMainLoopCallbacks;

    class TextConsole implements RMainLoopCallbacks

    {

        public void rWriteConsole(Rengine re, String text, int oType) {

            System.out.print(text);

        }

       

        public void rBusy(Rengine re, int which) {

            System.out.println("rBusy("+which+")");

        }

       

        public String rReadConsole(Rengine re, String prompt, int addToHistory) {

            System.out.print(prompt);

            try {

                BufferedReader br=new BufferedReader(new InputStreamReader(System.in));

                String s=br.readLine();

                return (s==null||s.length()==0)?s:s+" ";

            } catch (Exception e) {

                System.out.println("jriReadConsole exception: "+e.getMessage());

            }

            return null;

        }

       

        public void rShowMessage(Rengine re, String message) {

            System.out.println("rShowMessage ""+message+""");

        }

            

        public String rChooseFile(Rengine re, int newFile) {

             FileDialog fd = new FileDialog(new Frame(), (newFile==0)?"Select a file":"Select a new file", (newFile==0)?FileDialog.LOAD:FileDialog.SAVE);

             fd.show();

             String res=null;

             if (fd.getDirectory()!=null) res=fd.getDirectory();

             if (fd.getFile()!=null) res=(res==null)?fd.getFile():(res+fd.getFile());

             return res;

        }

       

        public void   rFlushConsole (Rengine re) {

        }

            

        public void   rLoadHistory  (Rengine re, String filename) {

        }                          

       

        public void   rSaveHistory  (Rengine re, String filename) {

        }                          

    }

    public class rtest {

        public static void main(String[] args) {

             // just making sure we have the right version of everything

             if (!Rengine.versionCheck()) {

                 System.err.println("** Version mismatch - Java files don't match library version.");

                 System.exit(1);

             }

            System.out.println("Creating Rengine (with arguments)");

                       // 1) we pass the arguments from the command line

                       // 2) we won't use the main loop at first, we'll start it later

                       //    (that's the "false" as second argument)

                       // 3) the callbacks are implemented by the TextConsole class above

                       Rengine re=new Rengine(args, false, new TextConsole());

            System.out.println("Rengine created, waiting for R");

                       // the engine creates R is a new thread, so we should wait until it's ready

            if (!re.waitForR()) {

                System.out.println("Cannot load R");

                return;

            }

                       /* High-level API - do not use RNI methods unless there is no other way

                                to accomplish what you want */

                       try {

                                REXP x;

                                re.eval("data(iris)",false);

                                System.out.println(x=re.eval("iris"));

                                // generic vectors are RVector to accomodate names

                                RVector v = x.asVector();

                                if (v.getNames()!=null) {

                                         System.out.println("has names:");

                                         for (Enumeration e = v.getNames().elements() ; e.hasMoreElements() ;) {

                                                   System.out.println(e.nextElement());

                                         }

                                }

                                // for compatibility with Rserve we allow casting of vectors to lists

                                RList vl = x.asList();

                                String[] k = vl.keys();

                                if (k!=null) {

                                         System.out.println("and once again from the list:");

                                         int i=0; while (i<k.length) System.out.println(k[i++]);

                                }                          

                                // get boolean array

                                System.out.println(x=re.eval("iris[[1]]>mean(iris[[1]])"));

                                // R knows about TRUE/FALSE/NA, so we cannot use boolean[] this way

                                // instead, we use int[] which is more convenient (and what R uses internally anyway)

                                int[] bi = x.asIntArray();

                                {

                                    int i = 0; while (i<bi.length) { System.out.print(bi[i]==0?"F ":(bi[i]==1?"T ":"NA ")); i++; }

                                    System.out.println("");

                                }

                               

                                // push a boolean array

                                boolean by[] = { true, false, false };

                                re.assign("bool", by);

                                System.out.println(x=re.eval("bool"));

                                // asBool returns the first element of the array as RBool

                                // (mostly useful for boolean arrays of the length 1). is should return true

                                System.out.println("isTRUE? "+x.asBool().isTRUE());

                                // now for a real dotted-pair list:

                                System.out.println(x=re.eval("pairlist(a=1,b='foo',c=1:5)"));

                                RList l = x.asList();

                                if (l!=null) {

                                         int i=0;

                                         String [] a = l.keys();

                                         System.out.println("Keys:");

                                         while (i<a.length) System.out.println(a[i++]);

                                         System.out.println("Contents:");

                                         i=0;

                                         while (i<a.length) System.out.println(l.at(i++));

                                }

                                System.out.println(re.eval("sqrt(36)"));

                       } catch (Exception e) {

                                System.out.println("EX:"+e);

                                e.printStackTrace();

                       }

                      

                       // Part 2 - low-level API - for illustration purposes only!

                       //System.exit(0);

                      

            // simple assignment like a<-"hello" (env=0 means use R_GlobalEnv)

            long xp1 = re.rniPutString("hello");

            re.rniAssign("a", xp1, 0);

            // Example: how to create a named list or data.frame

            double da[] = {1.2, 2.3, 4.5};

            double db[] = {1.4, 2.6, 4.2};

            long xp3 = re.rniPutDoubleArray(da);

            long xp4 = re.rniPutDoubleArray(db);

           

            // now build a list (generic vector is how that's called in R)

            long la[] = {xp3, xp4};

            long xp5 = re.rniPutVector(la);

            // now let's add names

            String sa[] = {"a","b"};

            long xp2 = re.rniPutStringArray(sa);

            re.rniSetAttr(xp5, "names", xp2);

            // ok, we have a proper list now

            // we could use assign and then eval "b<-data.frame(b)", but for now let's build it by hand:      

            String rn[] = {"1", "2", "3"};

            long xp7 = re.rniPutStringArray(rn);

            re.rniSetAttr(xp5, "row.names", xp7);

           

            long xp6 = re.rniPutString("data.frame");

            re.rniSetAttr(xp5, "class", xp6);

           

            // assign the whole thing to the "b" variable

            re.rniAssign("b", xp5, 0);

           

            {

                System.out.println("Parsing");

                long e=re.rniParse("data(iris)", 1);

                System.out.println("Result = "+e+", running eval");

                long r=re.rniEval(e, 0);

                System.out.println("Result = "+r+", building REXP");

                REXP x=new REXP(re, r);

                System.out.println("REXP result = "+x);

            }

            {

                System.out.println("Parsing");

                long e=re.rniParse("iris", 1);

                System.out.println("Result = "+e+", running eval");

                long r=re.rniEval(e, 0);

                System.out.println("Result = "+r+", building REXP");

                REXP x=new REXP(re, r);

                System.out.println("REXP result = "+x);

            }

            {

                System.out.println("Parsing");

                long e=re.rniParse("names(iris)", 1);

                System.out.println("Result = "+e+", running eval");

                long r=re.rniEval(e, 0);

                System.out.println("Result = "+r+", building REXP");

                REXP x=new REXP(re, r);

                System.out.println("REXP result = "+x);

                String s[]=x.asStringArray();

                if (s!=null) {

                    int i=0; while (i<s.length) { System.out.println("["+i+"] ""+s[i]+"""); i++; }

                }

            }

            {

                System.out.println("Parsing");

                long e=re.rniParse("rnorm(10)", 1);

                System.out.println("Result = "+e+", running eval");

                long r=re.rniEval(e, 0);

                System.out.println("Result = "+r+", building REXP");

                REXP x=new REXP(re, r);

                System.out.println("REXP result = "+x);

                double d[]=x.asDoubleArray();

                if (d!=null) {

                    int i=0; while (i<d.length) { System.out.print(((i==0)?"":", ")+d[i]); i++; }

                    System.out.println("");

                }

                System.out.println("");

            }

            {

                REXP x=re.eval("1:10");

                System.out.println("REXP result = "+x);

                int d[]=x.asIntArray();

                if (d!=null) {

                    int i=0; while (i<d.length) { System.out.print(((i==0)?"":", ")+d[i]); i++; }

                    System.out.println("");

                }

            }

            re.eval("print(1:10/3)");

           

             if (true) {

                 // so far we used R as a computational slave without REPL

                 // now we start the loop, so the user can use the console

                 System.out.println("Now the console is yours ... have fun");

                 re.startMainLoop();

             } else {

                 re.end();

                 System.out.println("end");

             }

        }

    }

    package com.rTest;

    import java.io.*;

    import java.awt.*;

    import javax.swing.*;

    import org.rosuda.JRI.Rengine;

    import org.rosuda.JRI.REXP;

    import org.rosuda.JRI.RMainLoopCallbacks;

    import org.rosuda.JRI.RConsoleOutputStream;

    class TextConsole2 implements RMainLoopCallbacks

    {

        JFrame f;

            

        public JTextArea textarea = new JTextArea();

        public TextConsole2() {

            f = new JFrame();

            f.getContentPane().add(new JScrollPane(textarea));

            f.setSize(new Dimension(800,600));

            f.show();

        }

        public void rWriteConsole(Rengine re, String text, int oType) {

            textarea.append(text);

        }

       

        public void rBusy(Rengine re, int which) {

            System.out.println("rBusy("+which+")");

        }

       

        public String rReadConsole(Rengine re, String prompt, int addToHistory) {

            System.out.print(prompt);

            try {

                BufferedReader br=new BufferedReader(new InputStreamReader(System.in));

                String s=br.readLine();

                return (s==null||s.length()==0)?s:s+" ";

            } catch (Exception e) {

                System.out.println("jriReadConsole exception: "+e.getMessage());

            }

            return null;

        }

       

        public void rShowMessage(Rengine re, String message) {

            System.out.println("rShowMessage ""+message+""");

        }

       

        public String rChooseFile(Rengine re, int newFile) {

             FileDialog fd = new FileDialog(f, (newFile==0)?"Select a file":"Select a new file", (newFile==0)?FileDialog.LOAD:FileDialog.SAVE);

             fd.show();

             String res=null;

             if (fd.getDirectory()!=null) res=fd.getDirectory();

             if (fd.getFile()!=null) res=(res==null)?fd.getFile():(res+fd.getFile());

             return res;

        }

       

        public void   rFlushConsole (Rengine re) {

             }

       

        public void   rLoadHistory  (Rengine re, String filename) {

        }                          

       

        public void   rSaveHistory  (Rengine re, String filename) {

        }                          

    }

    public class rtest2 {

        public static void main(String[] args) {

            System.out.println("Press <Enter> to continue (time to attach the debugger if necessary)");

            try { System.in.read(); } catch(Exception e) {};

            System.out.println("Creating Rengine (with arguments)");

                       Rengine re=new Rengine(args, true, new TextConsole2());

            System.out.println("Rengine created, waiting for R");

            if (!re.waitForR()) {

                System.out.println("Cannot load R");

                return;

            }

                       System.out.println("re-routing stdout/err into R console");

                       System.setOut(new PrintStream(new RConsoleOutputStream(re, 0)));

                       System.setErr(new PrintStream(new RConsoleOutputStream(re, 1)));

                      

                       System.out.println("Letting go; use main loop from now on");

        }

    }

    运行即可 Rtest 运行结果如下:

    Creating Rengine (with arguments)

     

    R version 3.0.1 (2013-05-16) -- "Good Sport"

    Copyright (C) 2013 The R Foundation for Statistical Computing

    Platform: i386-w64-mingw32/i386 (32-bit)

     

    R is free software and comes with ABSOLUTELY NO WARRANTY.

    You are welcome to redistribute it under certain conditions.

    Type 'license()' or 'licence()' for distribution details.

     

    R is a collaborative project with many contributors.

    Type 'contributors()' for more information and

    'citation()' on how to cite R or R packages in publications.

     

    Type 'demo()' for some demos, 'help()' for on-line help, or

    'help.start()' for an HTML browser interface to help.

    Type 'q()' to quit R.

     

    [1] "LC_COLLATE=Chinese_People's Republic of China.936;LC_CTYPE=Chinese_People's Republic of China.936;LC_MONETARY=Chinese_People's Republic of China.936;LC_NUMERIC=C;LC_TIME=Chinese_People's Republic of China.936"

    Rengine created, waiting for R

    [VECTOR ([REAL* (5.1, 4.9, 4.7, 4.6, 5.0, 5.4, 4.6, 5.0, 4.4, 4.9, 5.4, 4.8, 4.8, 4.3, 5.8, 5.7, 5.4, 5.1, 5.7, 5.1, 5.4, 5.1, 4.6, 5.1, 4.8, 5.0, 5.0, 5.2, 5.2, 4.7, 4.8, 5.4, 5.2, 5.5, 4.9, 5.0, 5.5, 4.9, 4.4, 5.1, 5.0, 4.5, 4.4, 5.0, 5.1, 4.8, 5.1, 4.6, 5.3, 5.0, 7.0, 6.4, 6.9, 5.5, 6.5, 5.7, 6.3, 4.9, 6.6, 5.2, 5.0, 5.9, 6.0, 6.1, 5.6, 6.7, 5.6, 5.8, 6.2, 5.6, 5.9, 6.1, 6.3, 6.1, 6.4, 6.6, 6.8, 6.7, 6.0, 5.7, 5.5, 5.5, 5.8, 6.0, 5.4, 6.0, 6.7, 6.3, 5.6, 5.5, 5.5, 6.1, 5.8, 5.0, 5.6, 5.7, 5.7, 6.2, 5.1, 5.7, ... (50 more values follow))], [REAL* (3.5, 3.0, 3.2, 3.1, 3.6, 3.9, 3.4, 3.4, 2.9, 3.1, 3.7, 3.4, 3.0, 3.0, 4.0, 4.4, 3.9, 3.5, 3.8, 3.8, 3.4, 3.7, 3.6, 3.3, 3.4, 3.0, 3.4, 3.5, 3.4, 3.2, 3.1, 3.4, 4.1, 4.2, 3.1, 3.2, 3.5, 3.6, 3.0, 3.4, 3.5, 2.3, 3.2, 3.5, 3.8, 3.0, 3.8, 3.2, 3.7, 3.3, 3.2, 3.2, 3.1, 2.3, 2.8, 2.8, 3.3, 2.4, 2.9, 2.7, 2.0, 3.0, 2.2, 2.9, 2.9, 3.1, 3.0, 2.7, 2.2, 2.5, 3.2, 2.8, 2.5, 2.8, 2.9, 3.0, 2.8, 3.0, 2.9, 2.6, 2.4, 2.4, 2.7, 2.7, 3.0, 3.4, 3.1, 2.3, 3.0, 2.5, 2.6, 3.0, 2.6, 2.3, 2.7, 3.0, 2.9, 2.9, 2.5, 2.8, ... (50 more values follow))], [REAL* (1.4, 1.4, 1.3, 1.5, 1.4, 1.7, 1.4, 1.5, 1.4, 1.5, 1.5, 1.6, 1.4, 1.1, 1.2, 1.5, 1.3, 1.4, 1.7, 1.5, 1.7, 1.5, 1.0, 1.7, 1.9, 1.6, 1.6, 1.5, 1.4, 1.6, 1.6, 1.5, 1.5, 1.4, 1.5, 1.2, 1.3, 1.4, 1.3, 1.5, 1.3, 1.3, 1.3, 1.6, 1.9, 1.4, 1.6, 1.4, 1.5, 1.4, 4.7, 4.5, 4.9, 4.0, 4.6, 4.5, 4.7, 3.3, 4.6, 3.9, 3.5, 4.2, 4.0, 4.7, 3.6, 4.4, 4.5, 4.1, 4.5, 3.9, 4.8, 4.0, 4.9, 4.7, 4.3, 4.4, 4.8, 5.0, 4.5, 3.5, 3.8, 3.7, 3.9, 5.1, 4.5, 4.5, 4.7, 4.4, 4.1, 4.0, 4.4, 4.6, 4.0, 3.3, 4.2, 4.2, 4.2, 4.3, 3.0, 4.1, ... (50 more values follow))], [REAL* (0.2, 0.2, 0.2, 0.2, 0.2, 0.4, 0.3, 0.2, 0.2, 0.1, 0.2, 0.2, 0.1, 0.1, 0.2, 0.4, 0.4, 0.3, 0.3, 0.3, 0.2, 0.4, 0.2, 0.5, 0.2, 0.2, 0.4, 0.2, 0.2, 0.2, 0.2, 0.4, 0.1, 0.2, 0.2, 0.2, 0.2, 0.1, 0.2, 0.2, 0.3, 0.3, 0.2, 0.6, 0.4, 0.3, 0.2, 0.2, 0.2, 0.2, 1.4, 1.5, 1.5, 1.3, 1.5, 1.3, 1.6, 1.0, 1.3, 1.4, 1.0, 1.5, 1.0, 1.4, 1.3, 1.4, 1.5, 1.0, 1.5, 1.1, 1.8, 1.3, 1.5, 1.2, 1.3, 1.4, 1.4, 1.7, 1.5, 1.0, 1.1, 1.0, 1.2, 1.6, 1.5, 1.6, 1.5, 1.3, 1.3, 1.3, 1.2, 1.4, 1.2, 1.0, 1.3, 1.2, 1.3, 1.3, 1.1, 1.3, ... (50 more values follow))], [FACTOR {levels=("setosa","versicolor","virginica"),ids=(0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2)}])]

    has names:

    Sepal.Length

    Sepal.Width

    Petal.Length

    Petal.Width

    Species

    and once again from the list:

    Sepal.Length

    Sepal.Width

    Petal.Length

    Petal.Width

    Species

    [BOOLi* ]

    F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F T T T F T F T F T F F T T T F T F F T F T T T T T T T T T F F F F T F T T T F F F T F F F F F T F F T F T T T T F T T T T T T F F T T T T T T F T T T T T T T T T T T T T T T T T T T T F T T T T T T T

    [BOOLi* ]

    isTRUE? true

    [LIST [REAL* (1.0)]:[SYMBOL a],([LIST [STRING "foo"]:[SYMBOL b],([LIST [INT* (1, 2, 3, 4, 5)]:[SYMBOL c],(null)])])]

    Keys:

    a

    b

    c

    Contents:

    [REAL* (1.0)]

    [STRING "foo"]

    [INT* (1, 2, 3, 4, 5)]

    [REAL* (6.0)]

    Parsing

    Result = 59278824, running eval

    Result = 66228464, building REXP

    REXP result = [STRING "iris"]

    Parsing

    Result = 54717432, running eval

    Result = 59554488, building REXP

    REXP result = [VECTOR ([REAL* (5.1, 4.9, 4.7, 4.6, 5.0, 5.4, 4.6, 5.0, 4.4, 4.9, 5.4, 4.8, 4.8, 4.3, 5.8, 5.7, 5.4, 5.1, 5.7, 5.1, 5.4, 5.1, 4.6, 5.1, 4.8, 5.0, 5.0, 5.2, 5.2, 4.7, 4.8, 5.4, 5.2, 5.5, 4.9, 5.0, 5.5, 4.9, 4.4, 5.1, 5.0, 4.5, 4.4, 5.0, 5.1, 4.8, 5.1, 4.6, 5.3, 5.0, 7.0, 6.4, 6.9, 5.5, 6.5, 5.7, 6.3, 4.9, 6.6, 5.2, 5.0, 5.9, 6.0, 6.1, 5.6, 6.7, 5.6, 5.8, 6.2, 5.6, 5.9, 6.1, 6.3, 6.1, 6.4, 6.6, 6.8, 6.7, 6.0, 5.7, 5.5, 5.5, 5.8, 6.0, 5.4, 6.0, 6.7, 6.3, 5.6, 5.5, 5.5, 6.1, 5.8, 5.0, 5.6, 5.7, 5.7, 6.2, 5.1, 5.7, ... (50 more values follow))], [REAL* (3.5, 3.0, 3.2, 3.1, 3.6, 3.9, 3.4, 3.4, 2.9, 3.1, 3.7, 3.4, 3.0, 3.0, 4.0, 4.4, 3.9, 3.5, 3.8, 3.8, 3.4, 3.7, 3.6, 3.3, 3.4, 3.0, 3.4, 3.5, 3.4, 3.2, 3.1, 3.4, 4.1, 4.2, 3.1, 3.2, 3.5, 3.6, 3.0, 3.4, 3.5, 2.3, 3.2, 3.5, 3.8, 3.0, 3.8, 3.2, 3.7, 3.3, 3.2, 3.2, 3.1, 2.3, 2.8, 2.8, 3.3, 2.4, 2.9, 2.7, 2.0, 3.0, 2.2, 2.9, 2.9, 3.1, 3.0, 2.7, 2.2, 2.5, 3.2, 2.8, 2.5, 2.8, 2.9, 3.0, 2.8, 3.0, 2.9, 2.6, 2.4, 2.4, 2.7, 2.7, 3.0, 3.4, 3.1, 2.3, 3.0, 2.5, 2.6, 3.0, 2.6, 2.3, 2.7, 3.0, 2.9, 2.9, 2.5, 2.8, ... (50 more values follow))], [REAL* (1.4, 1.4, 1.3, 1.5, 1.4, 1.7, 1.4, 1.5, 1.4, 1.5, 1.5, 1.6, 1.4, 1.1, 1.2, 1.5, 1.3, 1.4, 1.7, 1.5, 1.7, 1.5, 1.0, 1.7, 1.9, 1.6, 1.6, 1.5, 1.4, 1.6, 1.6, 1.5, 1.5, 1.4, 1.5, 1.2, 1.3, 1.4, 1.3, 1.5, 1.3, 1.3, 1.3, 1.6, 1.9, 1.4, 1.6, 1.4, 1.5, 1.4, 4.7, 4.5, 4.9, 4.0, 4.6, 4.5, 4.7, 3.3, 4.6, 3.9, 3.5, 4.2, 4.0, 4.7, 3.6, 4.4, 4.5, 4.1, 4.5, 3.9, 4.8, 4.0, 4.9, 4.7, 4.3, 4.4, 4.8, 5.0, 4.5, 3.5, 3.8, 3.7, 3.9, 5.1, 4.5, 4.5, 4.7, 4.4, 4.1, 4.0, 4.4, 4.6, 4.0, 3.3, 4.2, 4.2, 4.2, 4.3, 3.0, 4.1, ... (50 more values follow))], [REAL* (0.2, 0.2, 0.2, 0.2, 0.2, 0.4, 0.3, 0.2, 0.2, 0.1, 0.2, 0.2, 0.1, 0.1, 0.2, 0.4, 0.4, 0.3, 0.3, 0.3, 0.2, 0.4, 0.2, 0.5, 0.2, 0.2, 0.4, 0.2, 0.2, 0.2, 0.2, 0.4, 0.1, 0.2, 0.2, 0.2, 0.2, 0.1, 0.2, 0.2, 0.3, 0.3, 0.2, 0.6, 0.4, 0.3, 0.2, 0.2, 0.2, 0.2, 1.4, 1.5, 1.5, 1.3, 1.5, 1.3, 1.6, 1.0, 1.3, 1.4, 1.0, 1.5, 1.0, 1.4, 1.3, 1.4, 1.5, 1.0, 1.5, 1.1, 1.8, 1.3, 1.5, 1.2, 1.3, 1.4, 1.4, 1.7, 1.5, 1.0, 1.1, 1.0, 1.2, 1.6, 1.5, 1.6, 1.5, 1.3, 1.3, 1.3, 1.2, 1.4, 1.2, 1.0, 1.3, 1.2, 1.3, 1.3, 1.1, 1.3, ... (50 more values follow))], [FACTOR {levels=("setosa","versicolor","virginica"),ids=(0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2)}])]

    Parsing

    Result = 54722488, running eval

    Result = 59554264, building REXP

    REXP result = [STRING* ("Sepal.Length", "Sepal.Width", "Petal.Length", "Petal.Width", "Species")]

    [0] "Sepal.Length"

    [1] "Sepal.Width"

    [2] "Petal.Length"

    [3] "Petal.Width"

    [4] "Species"

    Parsing

    Result = 54722392, running eval

    Result = 58316336, building REXP

    REXP result = [REAL* (-0.18945291321042293, -1.849701024870639, -1.5554362607982648, 0.5990838636624077, -0.3034793177677859, -1.7781090129037724, 0.35644623327794134, -0.17655333079642885, -0.4089712138070159, -1.9775440799762682)]

    -0.18945291321042293, -1.849701024870639, -1.5554362607982648, 0.5990838636624077, -0.3034793177677859, -1.7781090129037724, 0.35644623327794134, -0.17655333079642885, -0.4089712138070159, -1.9775440799762682

     

    REXP result = [INT* (1, 2, 3, 4, 5, 6, 7, 8, 9, 10)]

    1, 2, 3, 4, 5, 6, 7, 8, 9, 10

     [1] 0.3333333 0.6666667 1.0000000 1.3333333 1.6666667 2.0000000 2.3333333

     [8] 2.6666667 3.0000000 3.3333333

    Now the console is yours ... have fun

    rBusy(0)

    > print("hello")

    rBusy(1)

    [1] "hello"

    rBusy(0)

    3.3     可能出现的错误

    3.3.1  Cannot find JRI native library!

    Press <Enter> to continue (time to attach the debugger if necessary)

     

    Creating Rengine (with arguments)

    Cannot find JRI native library!

    Please make sure that the JRI native library is in a directory listed in java.library.path.

     

    java.lang.UnsatisfiedLinkError: no jri in java.library.path

        at java.lang.ClassLoader.loadLibrary(ClassLoader.java:1860)

        at java.lang.Runtime.loadLibrary0(Runtime.java:845)

        at java.lang.System.loadLibrary(System.java:1084)

        at org.rosuda.JRI.Rengine.<clinit>(Rengine.java:19)

        at com.rTest.rtest2.main(rtest2.java:73)

    检查下path是否正确,如果正确

    重启下Eclipse 即可,如果不行,重启电脑。

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  • 原文地址:https://www.cnblogs.com/tomcattd/p/3369938.html
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