Function to create new binary variables within existing dataframe? - r

Question

This question is related to a previous topic:
How to use custom function to create new binary variables within existing dataframe?
I would like to use a similar function but be able to use a vector to specify ICD9 diagnosis variables within the dataframe to search for (e.g., "diag_1", "diag_2","diag_1", etc )
I tried
y<-c("diag_1","diag_2","diag_1")
diagnosis_func(patient_db, y, "2851", "Anemia")
but I get the following error:
Error in `[[<-`(`*tmp*`, i, value = value) :
recursive indexing failed at level 2
Below is the working function by Benjamin from the referenced post. However, it works only from 1 diagnosis variable at a time. Ultimately I need to create a new binary variable that indicates if a patient has a specific diagnosis by querying the 25 diagnosis variables of the dataframe.
*targetcolumn is the icd9 diagnosis variables "diag_1"..."diag_20" is the one I would like to input as vector
diagnosis_func <- function(data, target_col, icd, new_col){
pattern <- sprintf("^(%s)",
paste0(icd, collapse = "|"))
data[[new_col]] <- grepl(pattern = pattern,
x = data[[target_col]]) + 0L
data
}
diagnosis_func(patient_db, "diag_1", "2851", "Anemia")
This non-function version works for multiple diagnosis. However I have not figured out how to use it in a function version as above.
pattern = paste("^(", paste0("2851", collapse = "|"), ")", sep = "")
df$anemia<-ifelse(rowSums(sapply(df[c("diag_1","diag_2","diag_3")], grepl, pattern = pattern)) != 0,"1","0")
Any help or guidance on how to get this function to work would be greatly appreciated.
Best,
Albit

Answer 1

Try this modified version of Benjamin's function:
diagnosis_func <- function(data, target_col, icd, new_col){
pattern <- sprintf("^(%s)",
paste0(icd, collapse = "|"))
new <- apply(data[target_col], 2, function(x) grepl(pattern=pattern, x)) + 0L
data[[new_col]] <- ifelse(rowSums(new)>0, 1,0)
data
}