In rainiercito/farsfunctions: Contains a few formulas for manipulating the data from the US National Highway Traffic Safety Administration's Fatality Analysis Reporting System

This set of functions compose a Dummy R package that helps me to learn how to build and document R packages. For more details on learning how to build R packages see the Coursera Building R Packages Course at http://coursera.org.

To test the far_funtions package functionality please follow the next directions

Instructions for testing the Package Functionality Accuracy

Use "test_dir("~/Desktop/CursoR2/farsfunctions/R/.")" to run all the test available in the fars_functions Package's R folder (test located inside the test_fars_functions.R script)

or

Use "test_file("~/Desktop/CursoR2/farsfunctions/R/test_farsfunctions.R")" to run all the test available inside the testing script test_fars_functions.R located inside the R folder of the fars_functions Package.

The code "fars_functions.R" must be sourced before executing the testing

or

Use Test your package with Ctrl/Cmd + Shift + T or devtools::test() that will execute the testthat.R file who looks inside the "tests dirrectory" at ("~farsfunctions/tests/testthat/.")" to run all the test available in the fars_functions Package's tests/thestthat folder (test located inside the test_fars_functions.R script)

The far_functions package contains a set of functions for manipulating the data from the US National Highway Traffic Safety Administration's Fatality Analysis Reporting System.

fars_read(filename) function

• the fars_read(filename) function returns a table wich contains the data from the US National Highway Traffic Safety Administration's Fatality Analysis Reporting System, which is a nationwide census providing the American public yearly data regarding fatal injuries suffered in motor vehicle traffic crashes. In order to work, the function uses the functions:
  • readr from the read_csv package
  • tbl_df from the dplyr package
  • the parameter filename which represents the place from where the data will be read.

fars_read <- function(filename) {
        if(!file.exists(filename))
                stop("file '", filename, "' does not exist")
        data <- suppressMessages({
                readr::read_csv(filename, progress = FALSE)
        })
        dplyr::tbl_df(data)
}

Some examples for using correctly and incorrectly the fars_read(filename) function are:

Correct way to use the fars_read(filename)

fars_read("/Users/1/Desktop/data/fars_data.zip")

Incorrect way to use the fars_read(filename)

fars_read()

make_filename(year) function

• the make_filename(year) function returns a file name of a table wich contains a slide of the data from the US National Highway Traffic Safety Administration's Fatality Analysis Reporting System from a desired year. The file name is composed by a definend string and the given year. In order to work, the function uses:
  • the parameter year which represents desired year for having a slide of the data collected from the US National Highway Traffic Safety Administration's Fatality Analysis Reporting System, which is a nationwide census providing the American public yearly data regarding fatal injuries suffered in motor vehicle traffic crashes

make_filename <- function(year) {
        year <- as.integer(year)
        sprintf("accident_%d.csv.bz2", year)
}

Some examples for using correctly and incorrectly the make_filename(year) function are:

Correct way to use the make_filename(year)

make_filename("2014")

Incorrect way to use the make_filename(year)

make_filename()

fars_read_years(years) function

• the fars_read_years(years) function returns a table wich contains a slide of the data from the US National Highway Traffic Safety Administration's Fatality Analysis Reporting System for a desired years. In order to work, the function uses the functions:
  • %>% from the magrittr package
  • mutate, select from the dplyr package
  • the parameter years which represents a desired list of years for selecting data collected from the US National Highway Traffic Safety Administration's Fatality Analysis Reporting System, which is a nationwide census providing the American public yearly data regarding fatal injuries suffered in motor vehicle traffic crashes. If an invalid year is passaed as parameter, the data frame returned will be NULL an a warning will be delivered.

fars_read_years <- function(years) {
        lapply(years, function(year) {
                file <- make_filename(year)
                tryCatch({
                        dat <- fars_read(file)
                        dplyr::mutate(dat, year = year) %>% 
                                dplyr::select(MONTH, year)
                }, error = function(e) {
                        warning("invalid year: ", year)
                        return(NULL)
                })
        })
}

Some examples for using correctly and incorrectly the fars_read_years(years) function are:

Correct way to use the fars_read_years(years)

fars_read_years(c(2013,2014))

Incorrect way to use the fars_read_years(years)

fars_read_years()
fars_read_years("2013","2014")

fars_summarize_years(years) function

• the fars_summarize_years(years) function returns a summary table wich contains the number of accidents grouped by year and month of the given list of years. In order to work, the function uses the functions:
  • spread from the tidyr package
  • bind_rows, group_by and summarize from the dplyr package
  • the parameter years which represents a desired list of years for selecting data collected from the US National Highway Traffic Safety Administration's Fatality Analysis Reporting System, which is a nationwide census providing the American public yearly data regarding fatal injuries suffered in motor vehicle traffic crashes to be summarized. If an invalid year is passaed as parameter, the data frame returned will be NULL an a warning will be delivered.

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(year, n)
}

Some examples for using correctly and incorrectly the fars_summarize_years(years) function are:

Correct way to use the fars_summarize_years(years)

fars_read_years(c(2013,2014))

Incorrect way to use the fars_summarize_years(years)

fars_read_years()
fars_read_years("2013","2014")

fars_map_state(state.num,year)

• the fars_map_state(state.num,year) function returns a plot of the information loaded (fatal accidents) for a given state and year. In order to work, the function uses the functions:
  • maps from the maps package
  • filter from the dplyr package
  • the parameters state.num and years which represents a desired state number and year the selected data collected from the US National Highway Traffic Safety Administration's Fatality Analysis Reporting System, which is a nationwide census providing the American public yearly data regarding fatal injuries suffered in motor vehicle traffic crashes needs to be ploted. If the state.num is invalid this function stops execution and prints an error message.

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)
        })
}

Some examples for using correctly and incorrectly the fars_summarize_years(years) function are:

Correct way to use the fars_map_state(state.num,year)

fars_map_state(10,2014)

Incorrect way to use the fars_map_state(state.num,year)

fars_map_state()
fars_map_state("10,2014")

rainiercito/farsfunctions documentation built on May 26, 2019, 9:54 p.m.