Changes

:'''1. Introduction'''::*Five features (addrline1, addrline2, city, country, postcode) in the table contain address information.::*Features addrline1, addrline2 and city are not cleaned. They have city, country and postcode information. ::*The object of this project is to extract city, country and postcode information from the three features above.::*By now, we only focus on cleaning American patents.

:'''2. Postcode(U.S.)'''

::U.S. post code follows the pattern [five digits - four digits]. In this way, U.S. patents can be extracted by searching for post code with regular expression

::For example,

::The extracted post code records are stored in table ptoassigneend_missus_final.