比较两个字典并打印差异

Question

I have taken the difference between values for two dictionaries. What I have currently works, but I want to print "dict1[x] - dict2[x]" to the file I write to in front of the results. Not just the results. How can I do this? Do I need a nested loop?

comparison = {x: dict1[x] - dict2[x] for x in dict1 if x in dict2}

file1 = open('Results.txt', 'w')
for key,value in comparison.iteritems():
    print >> file1, ('%s: %s' % (key,value)) 
file1.close()

Edit: example

The values stored in each dictionary are timestamps, so I want my final results to look like:

12:30-11:30 = 1:00 

Answer 1

You can make a tuple of dict1[x] and dict2[x] the key of the dict instead, and unpack accordingly when iterating over the dict items:

comparison = {(dict1[x], dict2[x]): dict1[x] - dict2[x] for x in dict1 if x in dict2}

file1 = open('Results.txt', 'w')
for (time1, time2), value in comparison.iteritems():
    print >> file1, ('%s-%s: %s' % (time1, time2, value)) 
file1.close()