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  • R study day01 — 简介、基本操作

    一、数据分析

      1、一般的数据分析过程

        数据采集、数据存储、数据分析、数据挖掘、数据可视化、进行决策

        (1)数据存储:存储到数据仓库(输入到计算机中存储为文件格式)。

        (2)数据挖掘:从大量的数据通过算法搜索隐藏于其中信息的过程,并不清楚能够挖掘出什么,即不能明确结果。

    二、R语言介绍

      1、R语言特点

        (1)有效的数据处理和保存机制

        (2)拥有一整套数组和矩阵的操作运算符

        (3)一系列连贯而又完整的数据分析中间工具

        (4)图形统计可以对数据直接进行分析和显示,可用于多种图形设备

        (5)一种相当完善、简洁和高效的程序设计语言

        (6)R语言是彻底面对对象的统计编程语言

        (7)R语言和其它编程语言、数据库之间有很好的接口

        (8)R语言是自由软件,可以放心大胆地使用,但其功能却不比任何其它同类软件差

        (9)R语言具有丰富的网上资源

      2、R的缺点

        (1)R软件不够规范,不容易上手,需要付出较多的努力,付出大量的学习成本

        (2)R扩展包太多,且学习难度大

    三、Rstudio基本操作

      1、工作目录

        (1)getwd() 用于查询当前工作目录

          

          (2)setwd()用于设置当前目录

            注意:路径名要加上“ ”,要将原本文件加的改成/

          

        (3)dir() 查询当前工作目录的文件列表

          

         注:如果想要改变默认工作目录,需要点击上方的Tools工具中的Global option中修改

          

      2、赋值运算

        (1)常用 <- 进行赋值,注:符号之间一定不要有空格

    > x <- 3
    > x
    [1] 3

        (2)<<- 用于强制赋值给一个全局变量而不是局部变量,编写函数会用到

      3、常用函数

        (1)sum(….),取得所有元素的最大值

    > sum(1, 3,5 ,6,9)
    [1] 24

        mean(….) 取得所有元素的平均值

    > x<-c(1,2,3,4,5,6,7,8)
    > mean(x)
    [1] 4.5
    > mean(1:8)
    [1] 4.5

        ls() 列出目前在工作空间中存在的变量名

    > ls()
    [1] "x"

        ls.str() 列出目前在工作空间中存在的变量的所有信息

    > ls.str()
    x :  num [1:8] 1 2 3 4 5 6 7 8

        str(变量名)列出变量的详细信息

    > str(x)
     num [1:8] 1 2 3 4 5 6 7 8

        rm(变量名)删除变量

    > rm(x)

        rm(list = ls())删除所有变量

        save.image()保存工作空间,默认保存在当前工作目录下的RData文件中(绘制的图片不会单独保存)

    > save.image()

    四、R包的安装

      (1).libPaths()能够显示当前库所在的位置

    > .libPaths()
    [1] "D:/R-3.6.2/library"

      (2)library()不加任何参数能显示当前库中的软件包

      (3)library(包名)载入包/也可以使用require(包名)载入包

    > library("grid")

      (4)R的基础包在R启动的时候就会被加载进来

      (5)help(package="包名")查看包的帮助文档

    > help(package = "grid")

      (6)library(help="包名")列出包的基本内容

    > library(help="grid")

      (7)ls("package:包名")列出包中包含的所有函数

    > ls("package:grid")
      [1] "absolute.size"        "addGrob"              "applyEdit"           
      [4] "applyEdits"           "arcCurvature"         "arrow"               
      [7] "arrowsGrob"           "ascentDetails"        "bezierGrob"          
     [10] "bezierPoints"         "calcStringMetric"     "childNames"          
     [13] "circleGrob"           "clipGrob"             "convertHeight"       
     [16] "convertNative"        "convertUnit"          "convertWidth"        
     [19] "convertX"             "convertY"             "current.parent"      
     [22] "current.rotation"     "current.transform"    "current.viewport"    
     [25] "current.vpPath"       "current.vpTree"       "curveGrob"           
     [28] "dataViewport"         "delayGrob"            "depth"               
     [31] "descentDetails"       "deviceDim"            "deviceLoc"           
     [34] "downViewport"         "draw.details"         "drawDetails"         
     [37] "editDetails"          "editGrob"             "emptyCoords"         
     [40] "engine.display.list"  "explode"              "forceGrob"           
     [43] "frameGrob"            "functionGrob"         "gEdit"               
     [46] "gEditList"            "get.gpar"             "getGrob"             
     [49] "getNames"             "gList"                "gpar"                
     [52] "gPath"                "grid.abline"          "grid.add"            
     [55] "grid.arrows"          "grid.bezier"          "grid.cap"            
     [58] "grid.circle"          "grid.clip"            "grid.collection"     
     [61] "grid.convert"         "grid.convertHeight"   "grid.convertWidth"   
     [64] "grid.convertX"        "grid.convertY"        "grid.copy"           
     [67] "grid.curve"           "grid.delay"           "grid.display.list"   
     [70] "grid.DLapply"         "grid.draw"            "grid.edit"           
     [73] "grid.force"           "grid.frame"           "grid.function"       
     [76] "grid.gedit"           "grid.get"             "grid.gget"           
     [79] "grid.grab"            "grid.grabExpr"        "grid.gremove"        
     [82] "grid.grep"            "grid.grill"           "grid.grob"           
     [85] "grid.layout"          "grid.legend"          "grid.line.to"        
     [88] "grid.lines"           "grid.locator"         "grid.ls"             
     [91] "grid.move.to"         "grid.multipanel"      "grid.newpage"        
     [94] "grid.null"            "grid.pack"            "grid.panel"          
     [97] "grid.path"            "grid.place"           "grid.plot.and.legend"
    [100] "grid.points"          "grid.polygon"         "grid.polyline"       
    [103] "grid.pretty"          "grid.raster"          "grid.record"         
    [106] "grid.rect"            "grid.refresh"         "grid.remove"         
    [109] "grid.reorder"         "grid.revert"          "grid.roundrect"      
    [112] "grid.segments"        "grid.set"             "grid.show.layout"    
    [115] "grid.show.viewport"   "grid.strip"           "grid.text"           
    [118] "grid.xaxis"           "grid.xspline"         "grid.yaxis"          
    [121] "grob"                 "grobAscent"           "grobCoords"          
    [124] "grobDescent"          "grobHeight"           "grobName"            
    [127] "grobPathListing"      "grobPoints"           "grobTree"            
    [130] "grobWidth"            "grobX"                "grobY"               
    [133] "gTree"                "heightDetails"        "is.grob"             
    [136] "is.unit"              "isEmptyCoords"        "layout.heights"      
    [139] "layout.torture"       "layout.widths"        "layoutRegion"        
    [142] "legendGrob"           "linesGrob"            "lineToGrob"          
    [145] "makeContent"          "makeContext"          "moveToGrob"          
    [148] "nestedListing"        "nullGrob"             "packGrob"            
    [151] "pathGrob"             "pathListing"          "placeGrob"           
    [154] "plotViewport"         "pointsGrob"           "polygonGrob"         
    [157] "polylineGrob"         "pop.viewport"         "popViewport"         
    [160] "postDrawDetails"      "preDrawDetails"       "push.viewport"       
    [163] "pushViewport"         "rasterGrob"           "recordGrob"          
    [166] "rectGrob"             "removeGrob"           "reorderGrob"         
    [169] "resolveHJust"         "resolveRasterSize"    "resolveVJust"        
    [172] "roundrectGrob"        "seekViewport"         "segmentsGrob"        
    [175] "setChildren"          "setGrob"              "showGrob"            
    [178] "showViewport"         "stringAscent"         "stringDescent"       
    [181] "stringHeight"         "stringWidth"          "textGrob"            
    [184] "unit"                 "unit.c"               "unit.length"         
    [187] "unit.pmax"            "unit.pmin"            "unit.rep"            
    [190] "upViewport"           "valid.just"           "validDetails"        
    [193] "viewport"             "viewport.layout"      "viewport.transform"  
    [196] "vpList"               "vpPath"               "vpStack"             
    [199] "vpTree"               "widthDetails"         "xaxisGrob"           
    [202] "xDetails"             "xsplineGrob"          "xsplinePoints"       
    [205] "yaxisGrob"            "yDetails"            

      (8)data(package = "包名")列出包中包含所有的数据集

    > data(package = "base")
    Warning message:
    In data(package = "base") : 數據機从程序包'base'移到了程序包'datasets'

      (9)detach("package:包名")从内存中移除包

      (10)remove.package("包名")删除已经安装的包

      (11)install.packages("包名")安装对应包

    五、数据结构

      1、定义:数据结构是计算机存储、组织数据的方式

      2、R中的数据类型

          数值型,数值可以用于直接结算,加减乘除

          字符串型,可以进行连接,转换,提取等

          逻辑性,真或者假

          日期型等

      3、普通的数据结构:向量、标量、列表、数组、多维数组

          特殊的数据结构:perl中的哈希,python中的字典、C语言中的指针等

      4、R对象:object,它是指可以赋值给变量的任何事物,包括常量、数据结构、函数,甚至图形。对象都拥有某种模式,描述了此对象是如何存储的,以及某个类

      5、R中的数据结构:向量、标量、矩阵、数组、列表、数据框因子、时间序列等。

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  • 原文地址:https://www.cnblogs.com/MurasameLory-chenyulong/p/14273827.html
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