The goal of this part is to write a function called agecount that returns the number of homicide victims of a given age. For most (but not all) records there is an indication of the age of the victim. Your function should take one argument, the age of the victim(s), extract the age of the victim from each record and then return a count of the nu…

agecount.R

# agecount.R

agecount <- function(age = NULL) {
  ## Check that "age" is non-NULL; else throw error
  if (is.null(age)) {
    stop("Age input cannot be NULL")
  }
  
  ## Read "homicides.txt" data file
  homicides <- readLines("homicides.txt")
  
  ## Extract ages of victims; ignore records where no age is
  ## given
  age_str = as.character(x=age)
  age_pattern = paste("", age_str, "years old")
  # print(age_pattern)
  length(grep(pattern=age_pattern, x=homicides))
  
  ## Return integer containing count of homicides for that age
}