How do I remove duplicate sites in google api search result?

The search result gives something like:

Title : The widgets co.
snippet : widgets co. blah blah blah
url : widgetco.com/page1/

Title : The widgets co.
snippet : widgets co. blah blah blah
url : widgetco.com/page1

I saw this type of duplicate twice in my search result, their only difference is the slash at the end of the url.

thanks in advance.