[Flatten dict] flatten nested dict #python

flatten-dict.py

# reference: https://stackoverflow.com/questions/6027558/flatten-nested-dictionaries-compressing-keys
import collections

def flatten_nested_dict(d, parent_key='', sep='_'):
  items = []
  for k, v in d.items():
    new_key = parent_key + sep + k if parent_key else k
    if isinstance(v, collections.MutableMapping):
      items.extend(flatten(v, new_key, sep=sep).items())
    else:
      items.append((new_key, v))
  return dict(items)