如何将R数据帧的两列转换为命名向量？
如果两列的格式使得一列包含向量值的名称，而另一列具有向量值，则我们可能希望将它们转换为向量。为此，我们只需读取向量的数据类型并使用结构函数对其进行结构化即可。
例子1
x1<-rep(c("C1","C2","C3","C4"),each=5)
x2<-rep(1:10,2)
df1<-data.frame(x1,x2)
df1输出结果
x1 x2 1 C1 1 2 C1 2 3 C1 3 4 C1 4 5 C1 5 6 C2 6 7 C2 7 8 C2 8 9 C2 9 10 C2 10 11 C3 1 12 C3 2 13 C3 3 14 C3 4 15 C3 5 16 C4 6 17 C4 7 18 C4 8 19 C4 9 20 C4 10 df1_vector<-structure(as.numeric(df1$x2),names=as.character(df1$x1)) df1_vector C1 C1 C1 C1 C1 C2 C2 C2 C2 C2 C3 C3 C3 C3 C3 C4 C4 C4 C4 C4 1 2 3 4 5 6 7 8 9 10 1 2 3 4 5 6 7 8 9 10
例子2
set.seed(111) y1<-LETTERS[1:20] y2<-rnorm(20,0.5) df2<-data.frame(y1,y2) df2
输出结果
y1 y2 1 A 0.735220712 2 B 0.169264128 3 C 0.188376176 4 D -1.802345658 5 E 0.329123955 6 F 0.640278225 7 G -0.997426656 8 H -0.510188419 9 I -0.448475605 10 J 0.006037783 11 K 0.326325872 12 L 0.093401220 13 M 2.345636264 14 N 0.894054110 15 O 1.297528501 16 P -1.066665360 17 Q 0.414148991 18 R 0.140860519 19 S -0.693608967 20 T 0.864186737 df2_vector<-structure(as.numeric(df2$y2),names=as.character(df2$y1)) df2_vector A B C D E F 0.735220712 0.169264128 0.188376176 -1.802345658 0.329123955 0.640278225 G H I J K L -0.997426656 -0.510188419 -0.448475605 0.006037783 0.326325872 0.093401220 M N O P Q R 2.345636264 0.894054110 1.297528501 -1.066665360 0.414148991 0.140860519 S T -0.693608967 0.864186737
例子3
z1<-rep(c("String1","String2","String3","String4","String5"),each=4)
z2<-letters[20:1]
df3<-data.frame(z1,z2)
df3输出结果
z1 z2 1 String1 t 2 String1 s 3 String1 r 4 String1 q 5 String2 p 6 String2 o 7 String2 n 8 String2 m 9 String3 l 10 String3 k 11 String3 j 12 String3 i 13 String4 h 14 String4 g 15 String4 f 16 String4 e 17 String5 d 18 String5 c 19 String5 b 20 String5 a df3_vector<-structure(as.character(df3$z2),names=as.character(df3$z1)) df3_vector String1 String1 String1 String1 String2 String2 String2 String2 String3 String3 "t" "s" "r" "q" "p" "o" "n" "m" "l" "k" String3 String3 String4 String4 String4 String4 String5 String5 String5 String5 "j" "i" "h" "g" "f" "e" "d" "c" "b" "a"