In MarijusB/building_first_R_package: Coursera’s: Building R Packages, First R Package

knitr::opts_chunk$set(
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{ setup} library(FirstRpackage)

The functions in this package are designed to process csv file data from the Fatality-Analysis-Reporting-System-(FARS). Available functionality allows us to query file names, load files if available, collect total incidents by month and display them on a map.

This is a package to analyze the Fatality Analysis Reporting System (FARS). This package was designed for the Week 4 final assignment for the "Building R Packages" course on Coursera.

The Data

The data in this package is pulled from the National Highway Traffic Safety Administration Fatality Analysis Reporting System.

(https://crashstats.nhtsa.dot.gov/#/DocumentTypeList/4)

Package functions

The package contains 5 functions that read US National Highway Traffic Safety Administration's Fatality Analysis Reporting System (FARS) data and summarize them.

fars_read

Function: fars_read, takes string filename as input and returns full data from the file in data frame. This function cheks if file exists. If the file does not exist, then the function stops, and displays a message that indicates the file does not exist. If the file does exist, than the file is read into R via the readr package. The package is than converted to a datafram using the dplyr package. Usage: fars_read(filename) Arguments: filename Example: fars_read("accident_2015.csv.bz2")

make_file_name

Function: make_filename, takes integer year as input and returns FARS source data filename for the given year. This function takes an input in the form of a four digits value, a year, for example 2015 and converts the input to an integer and holds it in a variable called year. Usage: make_filename(year) Arguments: year. A string or integer providing the correct year to use in the file name. Example: make_filename(2015)

fars_read_years

Function: fars_read_years, takes a vector of integer years as input and returns a list of data frames containing fatality incidents for every months for each given year. For every input, this function will call make_filename function, which creates the files name for the info in that year, then loads the created filename using fars_read function, and then filters the data to the month and years. Usage: fars_read_years(years) Arguments: years. the years to find files to bring into R. Can be single or multiple values. Examples: fars_read_years(years=c(2013,2015)) or fars_read_years(c(2014,2015))

fars_summarize_year

Function: fars_summarize_year takes a vector of integer years as input and returns a summarized data frame containing the number of incidents for every month & year. The dataframes are then unioned using a bind_rows function from dplyr. Produced df is grouped by the year and month. The total number of records is then summarized with summarize function The results are represented with months as rows and years as columns using the spread fnction from tidyr. Usage: fars_summarize_years(years) Arguments: years. Example: fars_summarize_years(2013)

fars_map_state

Function: fars_map_state, takes an integer state number and integer year as inputs and returns a state map with plots, where each dot represents a fatality incident. Year is converted to a filename with make_filename function. The state number is set to an integer value. Data is filtered using dplyr. Thresholds for lat & long are set, if it goes above or below, it gets a null value. accident locations are then plotted. Usage: fars_summarize_years(years) Arguments: state.num & year. Both integer values. Examples: fars_map_state(1, 2015)

MarijusB/building_first_R_package documentation built on Aug. 6, 2020, 12:12 a.m.