Question

I have a function:

ncount <- function(num = NULL) {

 toRead <- readLines("abc.txt")
 n <- as.character(num)
 x <- grep("{"n"} number",toRead,value=TRUE)

}

While grep-ing, I want the num passed in the function to dynamically create the pattern to be searched? How can this be done in R? The text file has number and text in every line

Answer 1

You could use paste to concatenate strings:

grep(paste("{", n, "} number", sep = ""),homicides,value=TRUE)