49 lines
954 B
Python
49 lines
954 B
Python
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#!/usr/bin/env python
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# -*- encoding: utf-8 -*-
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"""
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Topic: 合并多个字典或映射
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Desc :
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"""
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from collections import ChainMap
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def combine_map():
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a = {'x': 1, 'z': 3 }
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b = {'y': 2, 'z': 4 }
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c = ChainMap(a,b)
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print(c['x']) # Outputs 1 (from a)
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print(c['y']) # Outputs 2 (from b)
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print(c['z']) # Outputs 3 (from a)
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print(len(c))
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print(list(c.keys()))
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print(list(c.values()))
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c['z'] = 10
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c['w'] = 40
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del c['x']
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print(a)
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# del c['y']
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values = ChainMap()
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values['x'] = 1
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# Add a new mapping
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values = values.new_child()
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values['x'] = 2
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# Add a new mapping
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values = values.new_child()
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values['x'] = 3
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print(values)
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print(values['x'])
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# Discard last mapping
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values = values.parents
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print(values['x'])
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# Discard last mapping
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values = values.parents
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print(values['x'])
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print(values)
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if __name__ == '__main__':
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combine_map()
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