How to replace values in single or multiple columns using either base R or dplyr?

[duttashi]

Often in a data analysis project, there arises a need or requirement to replace values in either a single or multiple column. In this question, I will address this issue from two perspectives;

• using baseR
• using mutate from tidyverse package

[duttashi]

Scenario: Replace multiple values by a single value in a column

Solution:

R> # create a dataframe
R> mydf<-data.frame(T=LETTERS[5:20],V=rnorm(16,10,1))
R> head(mydf)
  T      V
1 E 11.078
2 F 10.045
3 G  9.936
4 H  9.467
5 I 10.632
6 J 10.192

R> #1. Base R approach
R> mydf<-data.frame(T=LETTERS[5:20],V=rnorm(16,10,1))
R> levels(mydf$T)[levels(mydf$T) %in%  c("E","S","T")] <- "AB"
R> head(mydf)
   T     V
1 AB 8.525
2  F 8.985
3  G 9.873
4  H 9.619
5  I 8.875
6  J 9.246

# 2. Non-Tidyverse approach
# use recode() from library(car)
library(car)
mydf<-data.frame(T=LETTERS[5:20],V=rnorm(16,10,1))
R> mydf$T<- recode(mydf$T,"c('E','S','T')='AB'")
R> head(mydf)
   T      V
1 AB 10.813
2  F 10.561
3  G  9.863
4  H  9.866
5  I 10.558
6  J  9.233

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