In Python, how do I loop through the dictionary and change the value if it equals something?

Question

If the value is None, I\'d like to change it to \"\" (empty string).

I start off like this, but I forget:

for k, v in mydict.items():
    if v is Non         


        

Answer 1

You could create a dict comprehension of just the elements whose values are None, and then update back into the original:

tmp = dict((k,"") for k,v in mydict.iteritems() if v is None)
mydict.update(tmp)

Update - did some performance tests

Well, after trying dicts of from 100 to 10,000 items, with varying percentage of None values, the performance of Alex's solution is across-the-board about twice as fast as this solution.