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法學研究如何在R中提取命名向量中向量值的名稱？
如何在R中提取命名向量中向量值的名稱？
向量值的名稱是使用`names`函式建立的，可以使用相同的函式提取名稱。例如，如果我們有一個名為x的向量，它包含五個值（1到5），並且它們的名稱定義為first、second、third、fourth和fifth，那麼可以使用`names(x)[x==1]`提取x中值的名稱。
示例1
> x1<-1:4
> names(x1)<-c("one","two","three","four")
> x1輸出
one two three four 1 2 3 4
示例
> names(x1)[x1==1]
輸出
[1] "one"
示例
> names(x1)[x1==2]
輸出
[1] "two"
示例
> names(x1)[x1==3]
輸出
[1] "three"
示例
> names(x1)[x1==4]
輸出
[1] "four"
示例2
> x2<-sample(0:5,120,replace=TRUE) > x2
輸出
[1] 3 5 1 4 5 2 3 2 4 5 1 4 2 4 4 3 1 0 5 0 2 1 5 1 3 1 0 2 3 0 3 2 4 2 3 2 0 [38] 3 5 3 4 3 2 3 3 4 4 2 3 2 3 5 5 5 2 1 2 5 2 3 2 2 4 4 2 4 1 4 0 5 5 5 4 0 [75] 1 3 0 3 3 5 1 2 4 5 3 0 3 5 0 3 5 4 3 5 5 2 5 2 1 3 0 0 3 1 2 1 2 3 1 3 4 [112] 0 4 1 4 4 4 4 5 2
示例
> names(x2)<-sample(c("India","Russia","Turkey","France","Germany"),120,replace=TRUE)
> x2輸出
France Russia Russia Russia France Germany Germany France Turkey Germany 3 5 1 4 5 2 3 2 4 5 Germany India Turkey Russia Germany Turkey Germany Germany Russia Russia 1 4 2 4 4 3 1 0 5 0 Turkey France India France Germany Russia Russia Russia India Turkey 2 1 5 1 3 1 0 2 3 0 Turkey France India Germany Turkey India France India France Russia 3 2 4 2 3 2 0 3 5 3 India Turkey Germany Germany Turkey Russia Germany Turkey Germany Russia 4 3 2 3 3 4 4 2 3 2 Russia India Turkey Germany India France Russia Russia India France 3 5 5 5 2 1 2 5 2 3 France Russia India India India Turkey France India France India 2 2 4 4 2 4 1 4 0 5 Russia France India India France Turkey France Turkey Turkey Turkey 5 5 4 0 1 3 0 3 3 5 Turkey Turkey India India Russia Germany Turkey Germany France Russia 1 2 4 5 3 0 3 5 0 3 India Germany India India Germany Russia India Russia Russia Russia 5 4 3 5 5 2 5 2 1 3 Germany Russia Germany Turkey India Russia Germany Russia France India 0 0 3 1 2 1 2 3 1 3 France Germany Germany Germany Russia France India Turkey Russia Germany 4 0 4 1 4 4 4 4 5 2
示例
> names(x2)[x2==0]
輸出
[1] "Germany" "Russia" "Russia" "Turkey" "France" "France" "India" [8] "France" "Germany" "France" "Germany" "Russia" "Germany"
示例
> names(x2)[x2==1]
輸出
[1] "Russia" "Germany" "Germany" "France" "France" "Russia" "France" [8] "France" "France" "Turkey" "Russia" "Turkey" "Russia" "France" [15] "Germany"
示例
> names(x2)[x2==2]
輸出
[1] "Germany" "France" "Turkey" "Turkey" "Russia" "France" "Germany" [8] "India" "Germany" "Turkey" "Russia" "India" "Russia" "India" [15] "France" "Russia" "India" "Turkey" "Russia" "Russia" "India" [22] "Germany" "Germany"
示例
> names(x2)[x2==3]
輸出
[1] "France" "Germany" "Turkey" "Germany" "India" "Turkey" "Turkey" [8] "India" "Russia" "Turkey" "Germany" "Turkey" "Germany" "Russia" [15] "France" "Turkey" "Turkey" "Turkey" "Russia" "Turkey" "Russia" [22] "India" "Russia" "Germany" "Russia" "India"
示例
> names(x2)[x2==4]
輸出
[1] "Russia" "Turkey" "India" "Russia" "Germany" "India" "India" [8] "Russia" "Germany" "India" "India" "Turkey" "India" "India" [15] "India" "Germany" "France" "Germany" "Russia" "France" "India" [22] "Turkey"
示例
> names(x2)[x2==5]
輸出
[1] "Russia" "France" "Germany" "Russia" "India" "France" "India" [8] "Turkey" "Germany" "Russia" "India" "Russia" "France" "Turkey" [15] "India" "Germany" "India" "India" "Germany" "India" "Russia"
示例3
> x3<-sample(LETTERS[1:26],100,replace=TRUE) > x3
輸出
[1] "A" "U" "E" "B" "X" "S" "N" "C" "I" "W" "K" "R" "O" "G" "X" "G" "H" "C" [19] "G" "M" "M" "U" "O" "C" "C" "N" "W" "O" "W" "C" "B" "D" "L" "P" "W" "M" [37] "J" "L" "W" "A" "R" "M" "B" "U" "J" "B" "L" "W" "D" "Y" "J" "N" "I" "V" [55] "J" "S" "Q" "K" "K" "K" "J" "C" "H" "E" "C" "T" "R" "X" "I" "T" "Z" "H" [73] "E" "I" "Q" "E" "D" "C" "I" "T" "Y" "H" "K" "W" "X" "M" "Y" "E" "Q" "F" [91] "G" "Q" "Q" "O" "K" "L" "R" "Z" "F" "K"
示例
> names(x3)<-sample(c("C1","C2","C3","C4","C5"),100,replace=TRUE)
> x3輸出
C2 C4 C4 C4 C1 C3 C3 C1 C5 C2 C5 C5 C4 C1 C2 C5 C1 C3 C5 C3 "A" "U" "E" "B" "X" "S" "N" "C" "I" "W" "K" "R" "O" "G" "X" "G" "H" "C" "G" "M" C5 C3 C1 C1 C3 C4 C3 C1 C4 C2 C4 C1 C3 C3 C2 C1 C1 C3 C2 C2 "M" "U" "O" "C" "C" "N" "W" "O" "W" "C" "B" "D" "L" "P" "W" "M" "J" "L" "W" "A" C1 C2 C4 C1 C5 C1 C5 C1 C1 C3 C3 C1 C3 C1 C3 C4 C5 C1 C3 C3 "R" "M" "B" "U" "J" "B" "L" "W" "D" "Y" "J" "N" "I" "V" "J" "S" "Q" "K" "K" "K" C2 C1 C1 C5 C1 C3 C5 C1 C2 C1 C4 C5 C3 C1 C4 C4 C5 C3 C4 C5 "J" "C" "H" "E" "C" "T" "R" "X" "I" "T" "Z" "H" "E" "I" "Q" "E" "D" "C" "I" "T" C2 C4 C4 C4 C1 C5 C5 C1 C3 C2 C4 C2 C4 C1 C1 C1 C2 C3 C5 C5 "Y" "H" "K" "W" "X" "M" "Y" "E" "Q" "F" "G" "Q" "Q" "O" "K" "L" "R" "Z" "F" "K"
示例
> names(x3)[x3=="A"]
輸出
[1] "C2" "C2"
示例
> names(x3)[x3=="B"]
輸出
[1] "C4" "C4" "C4" "C1"
示例
> names(x3)[x3=="C"]
輸出
[1] "C1" "C3" "C1" "C3" "C2" "C1" "C1" "C3"
示例
> names(x3)[x3=="D"]
輸出
[1] "C1" "C1" "C5"
示例
> names(x3)[x3=="E"]
輸出
[1] "C4" "C5" "C3" "C4" "C1"
示例
> names(x3)[x3=="T"]
輸出
[1] "C3" "C1" "C5"
示例
> names(x3)[x3=="U"]
輸出
[1] "C4" "C3" "C1"
示例
> names(x3)[x3=="W"]
輸出
[1] "C2" "C3" "C4" "C2" "C2" "C1" "C4"
示例
> names(x3)[x3=="X"]
輸出
[1] "C1" "C2" "C1" "C1"
示例
> names(x3)[x3=="Y"]
輸出
[1] "C3" "C2" "C5"
示例
> names(x3)[x3=="Z"]
輸出
[1] "C4" "C3"
更新於：2020年11月19日
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