url
character string. The URL for the Polity IV data set you would
like to download. Note this is exclusively to download previous, IMF hosted,
versions of the data set. If a value is not supplied, then the 2015 IDB
hosted version will be downloaded. If a link is supplied it must be to a
Stata formated file.
duplicates
character specifying how to handle duplicated country-year
observations. Can be set to none
to do nothing, message
to
simply report duplicates, drop
to report and drop duplicates, and
return
to return a data frame with only duplicated observations
(see also fromLast
).