python RuntimeError: dictionary changed size during iteration

Question

I have obj like this

{hello: \'world\', \"foo.0.bar\": v1, \"foo.0.name\": v2, \"foo.1.bar\": v3}

It should be expand to

{         


        

Answer 1

For those experiencing

RuntimeError: dictionary changed size during iteration

also make sure you're not iterating through a defaultdict when trying to access a non-existent key! I caught myself doing that inside the for loop, which caused the defaultdict to create a default value for this key, causing the aforementioned error.

The solution is to convert your defaultdict to dict before looping through it, i.e.

d = defaultdict(int)
d_new = dict(d)

or make sure you're not adding/removing any keys while iterating through it.