Looping over dictionary

Question

My Code :

prices = {"banana": 4,"apple": 2,"orange": 1.5,"pear": 3}
stock = {"banana": 6,"apple": 0,"orange": 32,"pear": 15,}
for i in prices:
    print i
    print "price : %s" % prices[i]
    print "stock : %s" % stock[i]

My Output is:

orange
price : 1.5
stock : 32
pear
price : 3
stock : 15
banana
price : 4
stock : 6
apple
price : 2
stock : 0
None 

My question is why my output is printed from "orange" rather than "banana " then "apple then "orange: then "pear"?

Answer 1

Python dicts are unordered, that is their keys are not in lexicographical sorting. If you want the keys to be always ordered, use an OrderedDict instead. Otherwise, you can also sort the list and instead use for i in sorted(prices):.