Local helper to be reused.

check_input_file(filename = NULL, type = NULL, data_dir = NULL, year = NULL)

Arguments

filename

Character string of the filename of the .csv to read, if this is given, type and years determine whether there is a target to read, otherwise disk scan would be needed.

type

The type of file to be downloaded (e.g. 'Accidents', 'Casualties' or 'Vehicles'). Not case sensitive and searches using regular expressions ('acc' will work).

data_dir

Where sets of downloaded data would be found.

year

Single year for which data are to be read