official website: http://www.r-project.org/
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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Download R 3.1.2 for Windows (54 megabytes, 32/64 bit)
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 1.114: [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] 0.2var(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 6table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:
1. http://www.r-tutor.com/r-introduction/matrix/matrix-construction
2. http://eln.iis.sinica.edu.tw/lims/files/users/admin/rde_packagean_zhuang_ji_ji_ben_cao_zuo_.pdf
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