The OrderedDict is a subclass of the dictionary and it remembers the order in which the elements are added:

Syntax

d1 = collections.OrderedDict() 
d1 is ordered dictionary here.

Let's look at the comparison between dictionary and ordered dictionary:

import collections 
print 'Regular Dictionary'
d = {}
d['a']= 'SAS'
d['b']= 'PYTHON'
d['c']= 'R'

for k,v in d.items():
  print k, ":",v

print 'n Ordered dictionary'

d1 = collections.OrderedDict()
d1['a']= 'SAS'
d1['b']= 'PYTHON'
d1['c']= 'R'

for k,v in d1.items():
       print k, ":",v

Here, we create a normal dictionary and an ordered dictionary. Both the outputs are shown here:

As we could see, the ordered dictionary has retained the order in which the elements were added.