adii1823
25 lines
911 B
Python
25 lines
911 B
Python
# chainmap.py
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>>> from collections import ChainMap
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>>> default_connection = {'host': 'localhost', 'port': 4567}
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>>> connection = {'port': 5678}
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>>> conn = ChainMap(connection, default_connection) # map creation
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>>> conn['port'] # port is found in the first dictionary
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5678
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>>> conn['host'] # host is fetched from the second dictionary
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'localhost'
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>>> conn.maps # we can see the mapping objects
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[{'port': 5678}, {'host': 'localhost', 'port': 4567}]
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>>> conn['host'] = 'packtpub.com' # let's add host
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>>> conn.maps
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[{'port': 5678, 'host': 'packtpub.com'},
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{'host': 'localhost', 'port': 4567}]
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>>> del conn['port'] # let's remove the port information
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>>> conn.maps
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[{'host': 'packtpub.com'}, {'host': 'localhost', 'port': 4567}]
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>>> conn['port'] # now port is fetched from the second dictionary
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4567
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>>> dict(conn) # easy to merge and convert to regular dictionary
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{'host': 'packtpub.com', 'port': 4567}
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