CODEWITHSUNDEEP
rfor-loopif-statement
Saalva
Saalva

Reputation: 101

Adding characters/letters to value based on condition

Edit: The suggested code worked, so in total:

MyData$Numbers_2=with(MyData, ifelse(Numbers %in% MyVector, 
                    paste0("L_N", Numbers), 
                    paste0("L_", Numbers)))

This adds a column with the new (character) values.

I'd like to add a specific string of characters to every value in a column of a dataframe, based on the condition that the value is found in a vector. 

#Create Dataframe
MyData=data.frame(Numbers=c(85,84,7,9,82,5,81,80,10))
MyVector=c("80","81","82","83","84","85")

# for Loop with if else condition
for (Nr in MyVector) {MyData$Numbers_2=as.character(MyData$Numbers)
if(is.element(Nr,MyData$Numbers_2)) {MyData$Numbers_2= paste("L_N",MyData$Numbers_2, sep = "")}
else {MyData$Numbers_2= paste("L_",MyData$Numbers_2, sep = "")}
}

Basically, I'd like to have a result like this: L_N85, L_N84, L_7, L_9 etc.
But what I get is: L_N85, L_N84, L_N7, L_N9.
It adds L_N to every value in the column, and not only to specific ones. How to I have to change my code for that to happen?

Upvotes: 2

Views: 3767

Answers (1)

akrun
akrun

Reputation: 887038

Instead of a for loop or if/else we can do this with vectorized ifelse

with(MyData, ifelse(Numbers %in% MyVector, paste0("L_N", Numbers), paste0("L_", Numbers)))
#[1] "L_N85" "L_N84" "L_7"   "L_9"   "L_N82" "L_5"   "L_N81" "L_N80" "L_10"

Or with case_when from dplyr

library(dplyr)
MyData %>% 
     mutate(Numbers_2 = case_when(Numbers %in% MyVector ~ paste0("L_N", Numbers),
                                  TRUE ~ paste0("L_", Numbers)))

Upvotes: 2

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