How to merge 2 ordered dictionaries in python?

Question

I have 2 ordered dictionaries, like:

a = collections.OrderedDict() b = collections.OrderedDict() 

And they have stuff in them. How do I merge these 2? I tried:

mergeDict = dict(a.items() + b.items()) 

but doing this it's not a ordered dictionary anymore.

What I am looking for: if a = {1, 2, 5, 6} and b = [0, 7, 3, 9} then mergeDict = {1, 2, 5, 6, 0, 7, 3, 9}

Answer 1

Two ways (assuming Python 3.6):

1. Use "update method". Suppose there are two dictionaries:

   >>> d1 = collections.OrderedDict([('a', 1), ('b', 2)]) >>> d2 = {'c': 3, 'd': 4} >>> d1.update(d2) >>> d1 OrderedDict([('a', 1), ('b', 2), ('c', 3), ('d', 4)]) 

2. Second method using 'concatenation operator (+)'

   >>> d1 = collections.OrderedDict([('a', 1), ('b', 2)]) >>> d2 = {'c': 3, 'd': 4} >>> d3 = collections.OrderedDict(list(d1.items()) + list(d2.items())) >>> d3 OrderedDict([('a', 1), ('b', 2), ('c', 3), ('d', 4)]) 

Answer 2

from itertools import chain from collections import OrderedDict OrderedDict(chain(a.items(), b.items()))