Sum of columns with partial string match R

Question

I want to add two columns based on partial matches of their string value

a <- c("ChrM","ChrM","ChrM","ChrM","ChrM")
b <- c(5,6,7,10,11)
c <- c(0,0,3,0,1)
d <- c(2,1,0,1,0)

dfa <- data.table(a, b, c, d) 
colnames(dfa) <- c("ID","pos","cr H-MN-8A","cr H-MN-8B")
#I don't know how to make a column name with a string value (with " " and "_")
  ID     pos        cr H-MN-8A cr H-MN-8B
1 ChrM   5          0          2
2 ChrM   6          0          1
3 ChrM   7          3          0
4 ChrM  10          0          1
5 ChrM  11          1          0

I want to be able to add the last 2 columns "cr H-MN-8A","cr H-MN-8B" based on their partial string match "cr H-MN-8" and then write the result into a column while also comparing it to a value, so the return is true or false. I had something akin to

dfa <- lapply(dfa, function(x) x[, newval := as.numeric(col1+col2>=1)])

I have more than two string matches withing titles (they're all paired up on the same dataframe). Any ideas? Thanks!

(Don't know if it's relevant, but I'm using data.table

Answer 1

We can try the following data.table approach

dfa[,`H-MN-8` := as.numeric(rowSums(.SD) > 1), .SDcols = grep("cr H-MN-8", names(dfa))]

dfa
#     ID pos cr H-MN-8A cr H-MN-8B H-MN-8
#1: ChrM   5          0          2      1
#2: ChrM   6          0          1      0
#3: ChrM   7          3          0      1
#4: ChrM  10          0          1      0
#5: ChrM  11          1          0      0