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+# Title: Convert a date string column to a UNIX timestamp%0Aimport graphlab as gl%0Afrom datetime import datetime%0A# Requires you to 'pip install python-dateutil==1.5'%0Afrom dateutil import parser%0A%0Adef str_to_timestamp(the_str):%0A    try:%0A        dt = parser.parse(the_str)%0A    except:%0A        return None%0A%0A    # UNIX epoch is January 1, 1970%0A    return (dt - datetime(1970,1,1)).total_seconds()%0A%0A# 02/29/2001 is invalid, so should be 'None' in output%0Asf = gl.SFrame(%7B'date':%5B'2000-08-21','2013-06-08 17:25:00.12753','02/29/2001'%5D,'id':%5B1,2,3%5D%7D)%0Asf%5B'date'%5D = sf%5B'date'%5D.apply(str_to_timestamp)%0A

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