Simple Method of Traversing Dictionaries and Deleting Elements in Python

This article describes a simple way to traverse a dictionary and delete elements in Python. Shared for everyone's reference, as follows:

This way is definitely problematic:

d = {'a':1, 'b':2, 'c':3}
for key in d:
  d.pop(key)

Will report this error: RuntimeError: dictionary changed size during iteration

This way, Python2Is feasible, Python3And still report the above error.

d = {'a':1, 'b':2, 'c':3}
for key in d.keys():
  d.pop(key)

Python3The reason for the error is that the keys() function returns dict_keys instead of list. Python3A feasible way is as follows:

d = {'a':1, 'b':2, 'c':3}
for key in list(d):
  d.pop(key)

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I hope the content described in this article will be helpful to everyone in designing Python programs.

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