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How to reverse a vector in R?
Sometimes the vector values are recorded in the reverse order in R, therefore, we need to again reverse those vectors to get the actual order we want. For example, a sequence of numbers might be recorded as 1 to 20 but we wanted it to be from 20 to 1. The reversing of order of the vector values can be easily done with the help of rev function.
Examples
x1<-1:20
x1
[1] 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
rev(x1)
[1] 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1
x2<-letters[1:26]
x2
[1] "a" "b" "c" "d" "e" "f" "g" "h" "i" "j" "k" "l" "m" "n" "o" "p" "q" "r" "s"
[20] "t" "u" "v" "w" "x" "y" "z"
rev(x2)
[1] "z" "y" "x" "w" "v" "u" "t" "s" "r" "q" "p" "o" "n" "m" "l" "k" "j" "i" "h"
[20] "g" "f" "e" "d" "c" "b" "a"
x3<-LETTERS[1:26]
x3
[1] "A" "B" "C" "D" "E" "F" "G" "H" "I" "J" "K" "L" "M" "N" "O" "P" "Q" "R" "S"
[20] "T" "U" "V" "W" "X" "Y" "Z"
rev(x3)
[1] "Z" "Y" "X" "W" "V" "U" "T" "S" "R" "Q" "P" "O" "N" "M" "L" "K" "J" "I" "H"
[20] "G" "F" "E" "D" "C" "B" "A"
x4<-rep(c(1,2,3),each=10)
x4
[1] 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3 3 3 3 3 3 3 3 3
rev(x4)
[1] 3 3 3 3 3 3 3 3 3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1
x5<-c("USA","Canada","United Kingdom","Australia","New Zealand")
x5
[1] "USA" "Canada" "United Kingdom" "Australia"
[5] "New Zealand"
rev(x5)
[1] "New Zealand" "Australia" "United Kingdom" "Canada"
[5] "USA"
x6<-c("Name10","Name9","Name8","Name7","Name6","Name5","Name4","Name3","Name2","Name1")
x6
[1] "Name10" "Name9" "Name8" "Name7" "Name6" "Name5" "Name4" "Name3"
[9] "Name2" "Name1"
rev(x6)
[1] "Name1" "Name2" "Name3" "Name4" "Name5" "Name6" "Name7" "Name8"
[9] "Name9" "Name10"
x7<-c(TRUE,FALSE,TRUE,TRUE,FALSE,FALSE,FALSE,FALSE,TRUE,TRUE,FALSE,TRUE,TRUE)
x7
[1] TRUE FALSE TRUE TRUE FALSE FALSE FALSE FALSE TRUE TRUE FALSE TRUE
[13] TRUE
rev(x7)
[1] TRUE TRUE FALSE TRUE TRUE FALSE FALSE FALSE FALSE TRUE TRUE FALSE
[13] TRUE
x8<-c(14,78,25,17,12,19,17,35,26,17,84,45,14,23,52,7,2,19,18,25,65,74,78)
x8
[1] 14 78 25 17 12 19 17 35 26 17 84 45 14 23 52 7 2 19 18 25 65 74 78
rev(x8)
[1] 78 74 65 25 18 19 2 7 52 23 14 45 84 17 26 35 17 19 12 17 25 78 14
x9<-c(1.05,3.21,10.4,7.01,5.02,3.6,5.01,8.2,5.9,4.3,4.58,1.57,2.48)
x9
[1] 1.05 3.21 10.40 7.01 5.02 3.60 5.01 8.20 5.90 4.30 4.58 1.57
[13] 2.48
rev(x9)
[1] 2.48 1.57 4.58 4.30 5.90 8.20 5.01 3.60 5.02 7.01 10.40 3.21
[13] 1.05
x10<-c(5,NA,25,36,TRUE,17,"",65,18,"Class")
x10
[1] "5" NA "25" "36" "TRUE" "17" "" "65" "18"
[10] "Class"
rev(x10)
[1] "Class" "18" "65" "" "17" "TRUE" "36" "25" NA
[10] "5"
Updated on: 21-Aug-2020
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