django python：如何使json從Django查詢集

Question

我有一個查詢集，返回轉換列表後的json字符串。

[{"pid": 1, "loc": "KL", "sid": 1, "sd": "south-1"}, 
{"pid": 1, "loc": "KL", "sid": 2, "sd": "north-5"},  
{"pid": 1, "loc": "KL", "sid": 3, "sd": "west-3"} 
] 

我已經嘗試了許多串行選擇，但不知道如何作出上述爲：

[{"pid": 1, 
    "s": [{"sid": 1, "sd": "south-1", 
     "sid": 2, "sd": "north-5", 
     "sid": 3, "sd": "west-3" 
     }] 
}] 

Answer 1

首先，有一個在你的預期輸出錯誤。你大概的意思是：

[{"pid": 1, 
    "s": [{"sid": 1, "sd": "south-1"}, 
     {"sid": 2, "sd": "north-5"}, 
     {"sid": 3, "sd": "west-3"} 
     ], 
    "loc": "KL" 
}] 

即s應該是一個字典列表，而不是一個字典（和衝突鍵）。我已添加"loc": "KL"，因爲它看起來像缺少了。

假設每個查詢只能返回相同pid和loc，您可以創建s與原查詢中的每個sid和sd列表：

>>> q = ... # as above 
>>> r = {"pid": q[0]["pid"], "loc": q[0]["loc"]} # since pid and loc are always the same 
>>> r["s"] = [{"sid": x["sid"], "sd": x["sd"]} for x in q] 
>>> print r 
[{'pid': 1, 
    's': [{'sid': 1, 'sd': 'south-1'}, 
     {'sid': 2, 'sd': 'north-5'}, 
     {'sid': 3, 'sd': 'west-3'} 
     ], 
    'loc': 'KL' 
}] 
>>> print json.dumps(r) # gives the output as a json string