In sonam-sharma/addrepo: Geographical Map for Fatal injuries in motor vehicle traffic crashes

Reading the input file ,if it exists at the given path

This function checks whether a given file exists or not. If the file exists , it reads the file into a data frame. Otherwise it throws an error with the message "File does not exists". R will check the given file in the current working directory so ensure the file is present at the current working directory. This function uses two packages readr for read_csv to read a csv file and dplyr for tbl_df to convert data to data frame.

library(dplyr)
list.files()
file.exists("accident_2013.csv")

fars_read <- function(filename) {

   tryCatch({
  data1 <- suppressMessages({
 lapply(system.file('extdata', filename, package = 'mynewpackage'), read.csv)
  })
  },
  error = function(e) {
      stop("file '", filename, "' does not exist")
  })


 data2<-as.data.frame(data1) 
  dplyr::tbl_df(data2)
}

#head(data1)
fars_read("accident_2013.csv")

Generating name of the input file based on year provided.

This function returns the name of the file by formatting it with user inputted year.This function will also print the name of the file by concatenating string 'accident' with the year provided by the user.

make_filename <- function(year) {
  year <- as.integer(year)
  sprintf("accident_%d.csv", year)

}
make_filename(2013)

Selecting and printing the months present in the input file for the given year.

This function calls the make_filename function to return the name of the input file. It then reads the file and select and return the year and month present in the file for that year. If the year provided by user is not a valid year. it will throw an error. Package imported by this function is dplyr for mutate and select function.

fars_read_years <- function(years) {
  file<-dat<-MONTH<-NULL
  lapply(years, function(year) {
    file <- make_filename(year)

    tryCatch({
     dat <- fars_read(file)
    dat%>%dplyr::mutate_( year = ~year) %>%
        dplyr::select_(~MONTH, ~year)

    }, 
    error = function(e) {
      warning("invalid year: ", year)
      return(NULL)
    })
  })
}
fars_read_years(2013)

Total number of accidental injuries based on month for the given year.

This function reads the input file for the year provided by the user and then returns the number of observation for each month of the given year.If the year provided by user is not a valid year,this function will throw an error.Package imported by this function is dplyr for bind_rows, group_by and summarize function.

fars_summarize_years <- function(years) {
  dat_list <- fars_read_years(years)
  dplyr::bind_rows(dat_list) %>%
    dplyr::group_by_(~year, ~MONTH) %>%
    dplyr::summarize_(n = ~n()) %>%
    tidyr::spread_(key_col='year',value_col='n')
}
fars_summarize_years(2013)

Draws a geographical map for the accidental injuries for the given state and year.

This function reads the input file for the year provided by the user and returns a geographical map depicting the fatal injuries suffered in motor vehicle traffic crashes.If the year provided by user is not a valid year,this function will throw an error.Package imported by this function is dplyr for filter function,maps for map function and graphics for points function.

fars_map_state <- function(state.num, year) {
  filename <- make_filename(year)
  data <- fars_read(filename)
  state.num <- as.integer(state.num)

 # if(!(state.num %in% unique(data["STATE"])))
  #  stop("invalid STATE number: ", state.num)
  data.sub <- dplyr::filter_(data, ~STATE == state.num)
  if(nrow(data.sub) == 0L) {
    message("no accidents to plot")
    return(invisible(NULL))
  }
  is.na(data.sub$LONGITUD) <- data.sub$LONGITUD > 900
  is.na(data.sub$LATITUDE) <- data.sub$LATITUDE > 90
  with(data.sub, {
    maps::map("state", ylim = range(LATITUDE, na.rm = TRUE),
              xlim = range(LONGITUD, na.rm = TRUE))
    graphics::points(LONGITUD, LATITUDE, pch = 46)
  })
}


fars_map_state(1,2013)

sonam-sharma/addrepo documentation built on May 16, 2019, 11:08 a.m.