'''

The important thing about ordered dictionaries is that they remember the insertion order,

so when we iterate over them, they return in the order they were inserted.

for ordinary dictionaries equality is based on the key, value pairs

while for ordered dictionaries order of insertion is also taken into consideration.

'''

import collections

od1 = collections.OrderedDict()

od1['one'] = 1

od1['two'] = 2

od2 = collections.OrderedDict()

od2['two'] = 2

od2['one'] = 1

print(od1==od2)

'''

Similarly, when we add values from a list using update,

OrderedDict will retain the same order as the list.

'''

kvs = [('three',3),('four',4),('five',5)]

od1.update(kvs)

print(od1)

for k,v in od1.items():

print(k,v)

##############################################################

# print(sorted(od1.items(), key= lambda t: (4*t[1]) - t[1]**2))

od3 = collections.OrderedDict(sorted(od1.items(), key= lambda t: (4*t[1]) - t[1]**2))

print(od3)

print(od3.values())