Rick van Hattem
94 lines
2.1 KiB
ReStructuredText
94 lines
2.1 KiB
ReStructuredText
>>> nodes = [
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... ('a', 'b'),
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... ('a', 'c'),
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... ('b', 'a'),
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... ('b', 'd'),
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... ('c', 'a'),
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... ('d', 'a'),
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... ('d', 'b'),
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... ('d', 'c'),
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... ]
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------------------------------------------------------------------------------
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>>> graph = dict()
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>>> for from_, to in nodes:
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... if from_ not in graph:
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... graph[from_] = []
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... graph[from_].append(to)
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>>> import pprint
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>>> pprint.pprint(graph)
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{'a': ['b', 'c'],
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'b': ['a', 'd'],
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'c': ['a'],
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'd': ['a', 'b', 'c']}
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------------------------------------------------------------------------------
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>>> import collections
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>>> graph = collections.defaultdict(list)
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>>> for from_, to in nodes:
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... graph[from_].append(to)
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>>> import pprint
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>>> pprint.pprint(graph)
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defaultdict(<class 'list'>,
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{'a': ['b', 'c'],
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'b': ['a', 'd'],
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'c': ['a'],
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'd': ['a', 'b', 'c']})
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------------------------------------------------------------------------------
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>>> counter = collections.defaultdict(int)
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>>> counter['spam'] += 5
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>>> counter
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defaultdict(<class 'int'>, {'spam': 5})
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------------------------------------------------------------------------------
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>>> import collections
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>>> def tree(): return collections.defaultdict(tree)
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------------------------------------------------------------------------------
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>>> import json
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>>> import collections
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>>> def tree():
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... return collections.defaultdict(tree)
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>>> colours = tree()
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>>> colours['other']['black'] = 0x000000
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>>> colours['other']['white'] = 0xFFFFFF
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>>> colours['primary']['red'] = 0xFF0000
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>>> colours['primary']['green'] = 0x00FF00
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>>> colours['primary']['blue'] = 0x0000FF
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>>> colours['secondary']['yellow'] = 0xFFFF00
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>>> colours['secondary']['aqua'] = 0x00FFFF
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>>> colours['secondary']['fuchsia'] = 0xFF00FF
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>>> print(json.dumps(colours, sort_keys=True, indent=4))
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{
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"other": {
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"black": 0,
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"white": 16777215
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},
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"primary": {
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"blue": 255,
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"green": 65280,
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"red": 16711680
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},
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"secondary": {
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"aqua": 65535,
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"fuchsia": 16711935,
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"yellow": 16776960
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}
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}
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