R語言詢問問題

sammygumdom 2022-03-28 10:43:31 ‧ 756 瀏覽

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產生以下矩陣且命名為mat3：

m= matrix(1:20,5,4)
dimnames(m) <- list(c("stat1","stat2","stat3","stat4","stat5"),c("num1","num2","text","num3"))
m[, 1] <- c(3,5,1,9,2)
m[, 2] <- c(20,80,40,10,70)
m[, 3] <- c("k2","k5","k1","k3","k4")
m[, 4] <- c(800,200,900,400,600)

print(m)
1.依據text欄產生將k1~k5由小到大順序排列的新矩陣(其相對的其他欄位值都要一起變動)，且命名為mat3.text
2.依據num3欄產生將200~900由小到大順序排列的新矩陣(其相對的其他欄位值都要一起變動)，且命名為mat3.num3

obarisk iT邦研究生 2 級 ‧ 2022-03-29 09:58:30 檢舉

這題目不好。matrix 中的資料的型別都要相同
放了字串，整個 matrix 都會變字串

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2 個回答

海綿寶寶

iT邦大神 1 級 ‧ 2022-03-28 15:11:54

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may031556

iT邦新手 5 級 ‧ 2022-04-01 13:52:27

> m= matrix(1:20,5,4)
> dimnames(m) <- list(c("stat1","stat2","stat3","stat4","stat5"),c("num1","num2","text","num3"))
> m[, 1] <- c(3,5,1,9,2)
> m[, 2] <- c(20,80,40,10,70)
> m[, 3] <- c("k2","k5","k1","k3","k4")
> m[, 4] <- c(800,200,900,400,600)
> 
> print(m)
      num1 num2 text num3 
stat1 "3"  "20" "k2" "800"
stat2 "5"  "80" "k5" "200"
stat3 "1"  "40" "k1" "900"
stat4 "9"  "10" "k3" "400"
stat5 "2"  "70" "k4" "600"
> 
> # 產生以上矩陣且命名為mat3
> mat3 = m
> 
> # 依據text欄產生將k1~k5由小到大順序排列的新矩陣(其相對的其他欄位值都要一起變動)，且命名為mat3.text
> mat3.text = m[order(m[,"text"]),]
> print(mat3.text)
      num1 num2 text num3 
stat3 "1"  "40" "k1" "900"
stat1 "3"  "20" "k2" "800"
stat4 "9"  "10" "k3" "400"
stat5 "2"  "70" "k4" "600"
stat2 "5"  "80" "k5" "200"
> 
> 
> # 依據num3欄產生將200~900由小到大順序排列的新矩陣(其相對的其他欄位值都要一起變動)，且命名為mat3.num3
> mat3.num3 = m[order(m[,"num3"]),]
> print(mat3.num3)
      num1 num2 text num3 
stat2 "5"  "80" "k5" "200"
stat4 "9"  "10" "k3" "400"
stat5 "2"  "70" "k4" "600"
stat1 "3"  "20" "k2" "800"
stat3 "1"  "40" "k1" "900"