def loadRatings(ratingsFile):
    """
        载入得分
    """
    if not isfile(ratingsFile):
        print ("File %s does not exist." % ratingsFile)
        sys.exit(1)
    f = open(ratingsFile, 'r')
    ratings = filter(lambda r: r[2] > 0, [parseRating(line)[1] for line in f])
    f.close()
    if not ratings:
        print ("No ratings provided.")
        sys.exit(1)
    else:
        return ratings
myRatings = loadRatings("./recommendation_system_codes/movielens/ml-1m/ratings.dat")

myRatings[1]

myRatings[1]
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-22-961b4f3a9b9d> in <module>()
----> 1 myRatings[1]

TypeError: 'filter' object is not subscriptable

分析：

In Python 2.7 filter() returned a list, which has .pop() function.
In Python 3.x filter() returns a filter iterable object which does not.

Before you can .pop() from the filter in Python 3 you need to convert it to a list. So add e.g.

myRatings = list(myRatings) 
myRatings[1]

after the colors = filter(...) line. In Python 2.7 this will have no effect, so your code will continue to work there. See this question for more information and these docs.