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How to convert two columns of an R data frame to a named vector?
If two columns are of a form such that one column contains the name of the vector values and another column having the values of a vector then we might want to convert them into a vector. To do this, we can simply read the vectors with their data type and structure them with structure function.
Example 1
x1<-rep(c("C1","C2","C3","C4"),each=5)
x2<-rep(1:10,2)
df1<-data.frame(x1,x2)
df1Output
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
Example 2
set.seed(111) y1<-LETTERS[1:20] y2<-rnorm(20,0.5) df2<-data.frame(y1,y2) df2
Output
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
Example 3
z1<-rep(c("String1","String2","String3","String4","String5"),each=4)
z2<-letters[20:1]
df3<-data.frame(z1,z2)
df3Output
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"
Updated on: 21-Aug-2020
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