generating a multi dict with random numbers - python-2.7

Question

I have a data structure defined as follow :
reqList[i] = [multidict({
1: ['type1', randint(1, 5), randint(1, 5), randint(1, 5)],
2: ['type2', randint(1, 5), randint(1, 5), randint(1, 5)],
3: ['type3', randint(1, 5), randint(1, 5), randint(1, 5)],
4: ['type4', randint(1, 5), randint(1, 5), randint(1, 5)]
}),
multidict({
(1, 2): randint(500, 1000),
(2, 3): randint(500, 1000),
(3, 4): randint(500, 1000)
})]
I want to make the creation of this data structure automatic in a for loop for example. I did this:
nodes = {}
for j in range(1, randint(2, 5)):
nodes[j] = ['type%d' % j, randint(1, 5), randint(1, 5), randint(1, 5)]
edges = {}
for kk in range(1, len(nodes)):
edges[(kk, kk + 1)] = randint(500, 1000)
print "EDGES", edges
reqList[i] = [multidict(nodes),
multidict(edges)]
del (nodes, edges)
when I look into the outputed edges the order of the keys is not kept ! For example I am getting this:
EDGES {(1, 2): 583, (3, 4): 504, (2, 3): 993}
I want it to be :
EDGES {(1, 2): 583, (2, 3): 993, (3, 4): 504}
Does the way I am coding it is correct ? if not, could you suggest a better way knowing that I need to get the same result as in the first example?

Answer 1

Dictionary in 2.7 is unordered and you can not keep the order of insert, unless you manually keep a reference on what key got inserted and when in a separate list. The module collections contains a class called OrderedDict that acts like a dictionary but keeps the inserts in ordered, which is what you could use (it also uses a list to keep track of the keys insert but uses a double link list to speed up deletion of keys).
There's no other way other than these two method.
from collections import OrderedDict
nodes = {}
for j in range(1, randint(2, 5)):
nodes[j] = ['type%d' % j, randint(1, 5), randint(1, 5), randint(1, 5)]
edges = OrderedDict()
for kk in range(1, len(nodes)):
edges[(kk, kk + 1)] = randint(500, 1000)
print "EDGES", edges # EDGES OrderedDict([((1, 2), 898), ((2, 3), 814)])
print edges[(1,2)] # still yields the correct number
You can read more about OrderedDict here