how to assign list of values to a key using OrderedDict in python

Question

Hi want to have a ordered dictionary with keys having list of values.

from below code i could able to get a dictionary with list of keys but ordered of insertion is missing.

from collections import defaultdict

keys=['blk','pri','ani']
vals1=['blocking','primary','anim']
vals2=['S1','S2','S3']
dic = defaultdict(list)

i=0

for key in keys:
    dic[key].append(vals1[i])
    dic[key].append(vals2[i])

    i += 1

print dic

i get the following result

defaultdict(<type 'list'>, {'pri': ['primary', 'S2'], 'ani': ['anim', 'S3'], 'blk': ['blocking', 'S1']})

here i lost insert order.

I know defaultdict object in Python are unordered by definition.

And i know we need to Use OrderedDict if you need the order in which values were inserted (it's available in Python 2.7 and 3.x)

So changed my code as below

from below code i could able to get what i need.

from collections import defaultdict,OrderedDict

keys=['blk','pri','ani']
vals1=['blocking','primary','anim']
vals2=['S1','S2','S3']
dic = OrderedDict(defaultdict(list))

i=0

for key in keys:
    dic[key].append(vals1[i])
    dic[key].append(vals2[i])

    i += 1

print dic

and now i get the below error

Traceback (most recent call last):
  File "Dict.py", line 18, in <module>
    dic[key].append(vals1[i])
KeyError: 'blk' 

Can any one tell me how to get what i am trying.

Answer 1

Try this:

from collections import OrderedDict

keys=['blk','pri','ani']
vals1=['blocking','primary','anim']
vals2=['S1','S2','S3']
print OrderedDict(zip(keys, zip(vals1, vals2)))