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How to rename the factor levels of a factor variable by using mutate of dplyr package in R?
We know that a factor variable has many levels but it might be possible that the factor levels we have are not in the form as needed. For example, if we want to have capital letters as a factor level but the original data has small letters of English alphabets. In this situation we can rename those factor levels by using mutate of dplyr package.
Example
Consider the below data frame −
City <-rep(c("LA","NY","SF","LV"),each=5) Temp <-sample(1:50,20) df1 <-data.frame(City,Temp) df1
Output
City Temp 1 LA 2 2 LA 47 3 LA 7 4 LA 24 5 LA 11 6 NY 50 7 NY 9 8 NY 46 9 NY 18 10 NY 13 11 SF 37 12 SF 12 13 SF 8 14 SF 3 15 SF 19 16 LV 28 17 LV 20 18 LV 43 19 LV 1 20 LV 22
Renaming the levels of City variable −
Example
df1%>%mutate(City=recode(City,LA="Los Angeles",NY="New York",SF="San Francisco",LV="Las Vegas"))
Output
City Temp 1 Los Angeles 2 2 Los Angeles 47 3 Los Angeles 7 4 Los Angeles 24 5 Los Angeles 11 6 New York 50 7 New York 9 8 New York 46 9 New York 18 10 New York 13 11 San Francisco 37 12 San Francisco 12 13 San Francisco 8 14 San Francisco 3 15 San Francisco 19 16 Las Vegas 28 17 Las Vegas 20 18 Las Vegas 43 19 Las Vegas 1 20 Las Vegas 22
Let’s have a look at another example −
Example
Grade <-rep(c("A","B","C","D","E"),times=4) Score <-c(91:94,81:84,61:64,51:54,26:29) df2 <-data.frame(Grade,Score) df2
Output
Grade Score 1 A 91 2 B 92 3 C 93 4 D 94 5 E 81 6 A 82 7 B 83 8 C 84 9 D 61 10 E 62 11 A 63 12 B 64 13 C 51 14 D 52 15 E 53 16 A 54 17 B 26 18 C 27 19 D 28 20 E 29
Example
df2%>%mutate(Grade=recode(Grade,A="Excellent",B="Very Good",C="Good",D="Bad",E="Very Bad"))
Output
Grade Score 1 Excellent 91 2 Very Good 92 3 Good 93 4 Bad 94 5 Very Bad 81 6 Excellent 82 7 Very Good 83 8 Good 84 9 Bad 61 10 Very Bad 62 11 Excellent 63 12 Very Good 64 13 Good 51 14 Bad 52 15 Very Bad 53 16 Excellent 54 17 Very Good 26 18 Good 27 19 Bad 28 20 Very Bad 29
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