for i in range(4):
    for j in range(6):
        print i,j
        
0 0

0 1

0 2

0 3

0 4

0 5

1 0

1 1

1 2

1 3

1 4

1 5

2 0

2 1

2 2

2 3

2 4

2 5

3 0

3 1

3 2

3 3

3 4

3 5


for i in range(4):
    for j in range(i+1,6):
        print i,j
        
0 1

0 2

0 3

0 4

0 5

1 2

1 3

1 4

1 5

2 3

2 4

2 5

3 4

3 5


lst = [("x",4,"y"), ("a",8,"g"), ("e", 2, "f")]
import operator
x = sorted(lst,key=operator.itemgetter(2))
print x
[('e', 2, 'f'), ('a', 8, 'g'), ('x', 4, 'y')]


y = sorted(lst,key=operator.itemgetter(0,2))
print y
[('a', 8, 'g'), ('e', 2, 'f'), ('x', 4, 'y')]


lst.append(("e",3,"a"))
print lst
[('x', 4, 'y'), ('a', 8, 'g'), ('e', 2, 'f'), ('e', 3, 'a')]


y = sorted(lst,key=operator.itemgetter(0,2))
print y
[('a', 8, 'g'), ('e', 3, 'a'), ('e', 2, 'f'), ('x', 4, 'y')]


y = sorted(lst,key=operator.itemgetter(0,2), reverse=True)
print y
[('x', 4, 'y'), ('e', 2, 'f'), ('e', 3, 'a'), ('a', 8, 'g')]



# below is the output from running SimpleFoodReader.
# Although items looks like a list of strings, note its type is a string, 
# not a list. It is a string that looks like a list of strings!
# Also note that ratings looks like a dictionary, but its type is also
# a string, a string that looks like a dictionary!
# We then use JSON to convert items into the list of strings named var, 
# and to convert ratings into the dictionary named dvar.
# 
items =  ["Nasher Cafe", "ABP", "WaDuke", "Loop", "Panda", "Penn Pavilion", "McDonalds", "Blue Express"]

ratings =  {"student1004": [0, 1, 0, 0, 1, 0, 5, 0], "student1001": [3, 3, -3, 5, 3, 1, 0, 0], "student1003": [5, -3, 3, 0, 3, 0, 3, -3], "student1002": [0, 1, 5, -3, 1, 0, 5, -3]}

# note the type of items and ratings next!
<type 'str'> <type 'str'>

#after applying json.load, var is now a list. Ignore the u in front of
# each string, that just means its unicode. 
<type 'list'> [u'Nasher Cafe', u'ABP', u'WaDuke', u'Loop', u'Panda', u'Penn Pavilion', u'McDonalds', u'Blue Express']

#after applying json.load, dvar is now a dictionary. Again ignore the u that 
#  appears before each string.
<type 'dict'> {u'student1004': [0, 1, 0, 0, 1, 0, 5, 0], u'student1001': [3, 3, -3, 5, 3, 1, 0, 0], u'student1003': [5, -3, 3, 0, 3, 0, 3, -3], u'student1002': [0, 1, 5, -3, 1, 0, 5, -3]}