R的package安裝及簡單入門

Taiwan

http://ftp.yzu.edu.tw/CRAN/
Department of Computer Science and Engineering, Yuan Ze University

http://cran.cs.pu.edu.tw/
Providence University, Taichung

http://cran.csie.ntu.edu.tw/
National Taiwan University, Taipei

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C:\Program Files\R\R-3.1.2

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開啟R, 好懷念的簡樸介面設計風格…

開始玩玩看!

> 提示符號輸入指令如下:

   1: > 6+4

   2: [1] 10

   3: > 6+4+10

   4: [1] 20

   5: > 4*2^2

   6: [1] 16

   7: > sqrt(120)

   8: [1] 10.95445

   9: > abs(-5)

  10: [1] 5

  11: > 1.2e10

  12: [1] 1.2e+10

  13: > 1.2e10/2

  14: [1] 6e+09

  15: > pi

  16: [1] 3.141593

  17: > format

  18: function (x, ...)

  19: UseMethod("format")

  20: <bytecode: 0x0000000014014fa8>

  21: <environment: namespace:base>

  22: >

測試matrix指令, 發現MATLAB語法還是比較直覺…

   1: > 1:6

   2: [1] 1 2 3 4 5 6

   3: > matrix(1:12, nrow =4, ncol=3)

   4:      [,1] [,2] [,3]

   5: [1,]    1    5    9

   6: [2,]    2    6   10

   7: [3,]    3    7   11

   8: [4,]    4    8   12

   9: > matrix(1:12/10, nrow =4, ncol=3)

  10:      [,1] [,2] [,3]

  11: [1,]  0.1  0.5  0.9

  12: [2,]  0.2  0.6  1.0

  13: [3,]  0.3  0.7  1.1

  14: [4,]  0.4  0.8  1.2

變數指派: 名稱= 物件or 名稱←物件

   1: > n1<--3

   2: > n1

   3: [1] -3

   4: > n2 = -3

矩陣運算

   1: > v1=matrix(1:12/10, nrow =4, ncol=3)

   2: > v1

   3:      [,1] [,2] [,3]

   4: [1,]  0.1  0.5  0.9

   5: [2,]  0.2  0.6  1.0

   6: [3,]  0.3  0.7  1.1

   7: [4,]  0.4  0.8  1.2

   8: > 10*v1

   9:      [,1] [,2] [,3]

  10: [1,]    1    5    9

  11: [2,]    2    6   10

  12: [3,]    3    7   11

  13: [4,]    4    8   12

  14: > 1+v1

  15:      [,1] [,2] [,3]

  16: [1,]  1.1  1.5  1.9

  17: [2,]  1.2  1.6  2.0

  18: [3,]  1.3  1.7  2.1

  19: [4,]  1.4  1.8  2.2

取出1,2列, 1~3行的資料

   1: > v1[1:2,1:3]

   2:      [,1] [,2] [,3]

   3: [1,]  0.1  0.5  0.9

   4: [2,]  0.2  0.6  1.0

矩陣布林運算

   1: > v1

   2:      [,1] [,2] [,3]

   3: [1,]  0.1  0.5  0.9

   4: [2,]  0.2  0.6  1.0

   5: [3,]  0.3  0.7  1.1

   6: [4,]  0.4  0.8  1.2

   7: > v1>0.5

   8:       [,1]  [,2] [,3]

   9: [1,] FALSE FALSE TRUE

  10: [2,] FALSE  TRUE TRUE

  11: [3,] FALSE  TRUE TRUE

  12: [4,] FALSE  TRUE TRUE

矩陣>0.5的數值取出

   1: > ind = v1>0.5

   2: > v1

   3:      [,1] [,2] [,3]

   4: [1,]  0.1  0.5  0.9

   5: [2,]  0.2  0.6  1.0

   6: [3,]  0.3  0.7  1.1

   7: [4,]  0.4  0.8  1.2

   8: > v1[ind]

   9: [1] 0.6 0.7 0.8 0.9 1.0 1.1 1.2

第1行第1~3列取平均

   1: > mean(v1[1:3,1])

   2: [1] 0.2

var(v1)

   1: > var(v1)

   2:            [,1]       [,2]       [,3]

   3: [1,] 0.01666667 0.01666667 0.01666667

   4: [2,] 0.01666667 0.01666667 0.01666667

   5: [3,] 0.01666667 0.01666667 0.01666667

輸入3x2的陣矩

   1: > B = matrix( c(1, 2, 3, 1.1, 1.5, 1.2), nrow=3, ncol=2)

   2: > B

   3:      [,1] [,2]

   4: [1,]    1  1.1

   5: [2,]    2  1.5

   6: [3,]    3  1.2

繪圖囉!!!

> plot(B[1:3, 1], B[1:3, 2])

初始化table, 內容為1:18也是同MATLAB column wise

   1: > table<-as.data.frame(matrix(1:18, ncol=6))

   2: > table

   3:   V1 V2 V3 V4 V5 V6

   4: 1  1  4  7 10 13 16

   5: 2  2  5  8 11 14 17

   6: 3  3  6  9 12 15 18

取出第1行全部

   1: > table[,1]

   2: [1] 1 2 3

取出第2行, V2的第一個字大寫!

   1: > table[,1]

   2: [1] 1 2 3

   3: > table$v2

   4: NULL

   5: > table$V2

   6: [1] 4 5 6

取出部分矩陣

   1: > table[2:3, 1:2]

   2:   V1 V2

   3: 2  2  5

   4: 3  3  6

table矩陣轉置(transpose)

   1: > t(table)

   2:    [,1] [,2] [,3]

   3: V1    1    2    3

   4: V2    4    5    6

   5: V3    7    8    9

   6: V4   10   11   12

   7: V5   13   14   15

   8: V6   16   17   18

列出目前workspace所有變數

   1: > ls()

   2: [1] "B"     "ind"   "n1"    "n2"    "table" "v1"    "x"     "x1"

   3: >

參考來源:

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