How do I replace all of one character string in one column with another column's character stri-CodePudding

Say I have a data frame that looks like this:

sample   tissue   disease
s1       brain    glioblastoma
s2       skin     melanoma
s3       liver    NA
s4       kidney   carcinoma
s5       nerve    NA

How would I go about replacing all NAs with "Normal [corresponding tissue]"? E.g., for sample 3, NA would be replaced with "liver normal" and for sample 5 NA would be replaced with "nerve normal".

I appreciate any help!

CodePudding user response：

We create a logical vector based on the NA occurrence in 'disease' and then paste the corresponding 'tissue' elements with 'normal' to update the 'disease' column

i1 <- is.na(df1$disease)
df1$disease[i1] <- paste(df1$tissue[i1], "normal")

Or more concisely in data.table

library(data.table)
setDT(df1)[is.na(disease), disease := paste0(tissue, 'normal')]