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How to replace a particular value in R data frame with a new value?
To replace a particular value in R data frame with a new value, we can use ifelse function where the new value will be placed after the condition and if the column values do not match the condition then the same column will be placed. For example, if we have a data frame called df that contains a column x having 20 values and some of them are 5 and if we want to replace 5 with 2 then we can use the command df$x<-ifelse(df$x==5,2,df$x)
Example
Consider the below data frame −
ID<-1:20 x<-rpois(20,2) df1<-data.frame(ID,x) df1
Output
ID x 1 1 2 2 2 2 3 3 2 4 4 4 5 5 2 6 6 2 7 7 2 8 8 2 9 9 1 10 10 2 11 11 0 12 12 2 13 13 4 14 14 4 15 15 4 16 16 0 17 17 2 18 18 3 19 19 0 20 20 3
Replacing value 2 in column x with 3 −
Example
df1$x<-ifelse(df1$x==2,3,df1$x) df1
Output
ID x 1 1 3 2 2 3 3 3 3 4 4 4 5 5 3 6 6 3 7 7 3 8 8 3 9 9 1 10 10 3 11 11 0 12 12 3 13 13 4 14 14 4 15 15 4 16 16 0 17 17 3 18 18 3 19 19 0 20 20 3
Example
S.No<-1:20 y<-rpois(20,5) df2<-data.frame(S.No,y) df2
Output
S.No y 1 1 4 2 2 5 3 3 5 4 4 7 5 5 9 6 6 6 7 7 2 8 8 3 9 9 1 10 10 4 11 11 9 12 12 3 13 13 3 14 14 6 15 15 8 16 16 6 17 17 4 18 18 5 19 19 8 20 20 3
Replacing value 4 in column y with 0 −
Example
df2$y<-ifelse(df2$y==4,0,df2$y) df2
Output
S.No y 1 1 0 2 2 5 3 3 5 4 4 7 5 5 9 6 6 6 7 7 2 8 8 3 9 9 1 10 10 0 11 11 9 12 12 3 13 13 3 14 14 6 15 15 8 16 16 6 17 17 0 18 18 5 19 19 8 20 20 3
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