[英]Pymongo:iterating dictionary of a list of dictionary
Let us say I have a big collection including documents such as these: 可以说我收藏了很多这样的文件:
{"_id": 0,
"name":"John Doe",
"items": [
{"x":5,
"y":8,
"z":9},
{"x":4,
"y":2,
"z":1},
{"x":3,
"y":5,
"z":8}
]
}
I am fetching the collection into a variable called 'data' with pymongo and trying to iterate over the items in order to update some. 我正在使用pymongo将集合提取到名为“ data”的变量中,并尝试对项目进行迭代以更新一些项目。 I have tried to print those values with the following code:
我尝试使用以下代码打印这些值:
for i in data:
for j in data[i].get("items"):
pprint(j.get("x"))
and it gave an error: 它给出了一个错误:
pymongo.errors.InvalidOperation: cannot set options after executing query
Even if I get the items, I do not see a way to change data. 即使我得到了物品,也看不到更改数据的方法。 Why is this happening and how can I iterate through items and change their values?
为什么会发生这种情况?我如何遍历项目并更改其值?
How looks db query? db查询怎么样?
Try something like this for iteration: 尝试这样的迭代:
cursor = db.get_collection('some_collection').find()
for doc in cursor:
for item in doc['items']:
pprint(item.get('x'))
Let's say if you want to change the values of all x
. 假设您要更改所有
x
的值。
for i in data.get('items'):
# to change the values in items
# this will replace all values of key x
i['x'] = new_value
simply assign a new value to items
key. 只需为
items
键分配一个新值。
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