From flat to nested structure

[nilamo]

What about a dict, with the value being a list of every occurrence?

>>> data = '''a : one
...  b : two
...  c : three
...  d : four
...  a : five
...  b : six
...  c : seven
...  d : eight
...  e : nine'''.split('\n')
>>> data
['a : one', ' b : two', ' c : three', ' d : four', ' a : five', ' b : six', ' c : seven', ' d : eight', ' e : nine']
>>> parsed = {}
>>> for item in data:
...   key, value = item.split(':')
...   key = key.strip()
...   value = value.strip()
...   if key not in parsed:
...     parsed[key] = []
...   parsed[key].append(value)
...
>>> parsed
{'c': ['three', 'seven'], 'd': ['four', 'eight'], 'b': ['two', 'six'], 'a': ['one', 'five'], 'e': ['nine']}