How to delete items from a dictionary while iterating over it?

Question

Is it legitimate to delete items from a dictionary in Python while iterating over it?

For example:

for k, v in mydict.iteritems():
   if k == val:
           


        

Answer 1

There is a way that may be suitable if the items you want to delete are always at the "beginning" of the dict iteration

while mydict:
    key, value = next(iter(mydict.items()))
    if should_delete(key, value):
       del mydict[key]
    else:
       break

The "beginning" is only guaranteed to be consistent for certain Python versions/implementations. For example from What’s New In Python 3.7

the insertion-order preservation nature of dict objects has been declared to be an official part of the Python language spec.

This way avoids a copy of the dict that a lot of the other answers suggest, at least in Python 3.