On 2016-05-25, Daiyue Weng <daiyuew...@gmail.com> wrote:
> I want to find the maximal number of elements contained in a nested
> dictionary, e.g.
>
> data = {
> 'violations':
> {
> 'col1': {'err': [elem1, elem2, elem3]},
> 'col2': {'err': [elem1, elem2]}
> }
> }
>
> so to find the maximal number of elements in the lists for key 'err' in key
> 'col1' and 'col2'. Also key 'violations' may contain many keys (e.g. 'col1'
> , 'col2', 'col3' etc), so what's the best way to do this (using a loop)?
>
> max = 0for col in data.violations:
> if max < len(data.violations.col.err):
> max = len(data.violations.col.err)
In Python 3 you could do:
max((len(col["err"]) for col in data["violations"].values()), default=0)
In Python 2 you can do the same but you can't specify "default=0" and
so it will throw an exception if there are no lists found, so you
could use something like:
max_errs = 0
if data["violations"]:
max_errs = max(len(col["err"]) for col in data["violations"].values())
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