Iterating over key and value of defaultdict dictionaries

Question

The following works as expected:

d = [(1,2), (3,4)] for k,v in d:   print "%s - %s" % (str(k), str(v)) 

But this fails:

d = collections.defaultdict(int) d[1] = 2 d[3] = 4 for k,v in d:   print "%s - %s" % (str(k), str(v)) 

With:

Traceback (most recent call last):    File "<stdin>", line 1, in <module>   TypeError: 'int' object is not iterable  

Why? How can i fix it?

Answer 1

you need to iterate over dict.iteritems():

for k,v in d.iteritems():               # will become d.items() in py3k   print "%s - %s" % (str(k), str(v)) 

Update: in py3 V3.6+

for k,v in d.items():   print (f"{k} - {v}") 

Answer 2

if you are using Python 3.6

from collections import defaultdict  for k, v in d.items():     print(f'{k} - {v}')