PyMongo - Python 列表到 MongoDB 数据类型的转换

Question

我从以下请求中得到字符串格式的 json 响应：

results = requests.request("POST", url, data=json.dumps(payload), headers=header).json()['product']

示例输出： print(results) - 对象类型 = list'>

[
{
 'id': '123456',
 'product': 'XYZ',
 'exp_date': '03/01/2020',
 'amount': '30.5',
 'qty': '1'
},
{
 'id': '789012',
 'product': 'ABC',
 'exp_date': '04/15/2020',
 'amount': '22.57',
 'qty': '3'
},
{
 'id': '56789',
 'product': 'AAA',
 'exp_date': '03/29/2020',
 'amount': '',
 'qty': ' '
}
]

需要先将所有这些字段转换为特定的数据类型，然后作为文档插入到MongoDB中。

1. exp_date 到 日期/时间
2. 金额为 float()
3. 数量为 int()

进行数据类型转换的有效方法是什么？

正在考虑是否有可能像下面这样，还需要知道是否有任何空、空或空白字符串值，那么在数据类型转换期间如何将其替换为一些默认值？

new_result = []
for i in enumerate(results):
    i[exp_date] = datetime.strptime(i[exp_date],'%m/%d%Y').replace(hour=0, minute=0, second=0, microsecond=0)                         #check for empty/null/blank values and replace with default date
    new_result.append(i[exp_date])

for i in enumerate(results):
    i[amount] = float(i[amount])   #check for empty/null/blank values and replace with 0.00
    new_result.append(i[amount])

for i in enumerate(results):
    i[qty] = int(i[qty])           #check for empty/null/blank values and replace with 0
    new_result.append(i[qty])

db.collection.insert_many(new_result)

新列表输出应如下所示：print(new_result)

[
{
 "id": "123456",
 "product": "XYZ",
 "exp_date": 2020-03-01 00:00:00,
 "amount": 30.5,
 "qty": 1
},
{
 "id": "789012",
 "product": "ABC",
 "exp_date": 2020-04-15 00:00:00,
 "amount": 22.57,
 "qty": 3
},
{
 "id": "56789",
 "product": "AAA",
 "exp_date": 2020-03-29 00:00:00,
 "amount": 0.0,
 "qty": 0
}
]

Answer 1

你可以这样做：

import datetime

input_lst = [
{
 "id": "123456",
 "product": "XYZ",
 "exp_date": "03/01/2020",
 "amount": "30.5",
 "qty": "1"
},
{
 "id": "789012",
 "product": "ABC",
 "exp_date": "04/15/2020",
 "amount": "22.57",
 "qty": "3"
},
{
 "id": "56789",
 "product": "AAA",
 "exp_date": "03/29/2020",
 "amount": "",
 "qty": " "
}
]

output_lst = []


for dct in input_lst:
    tmp_dct = dct.copy()
    # amount - float, qty - int4
    try:
        tmp_dct['amount'] = float(dct['amount'])
    except:
        pass

    try:
        tmp_dct['qty'] = int(dct['qty'])
    except:
        pass

    try:
        tmp_dct['exp_date'] = datetime.datetime.strptime(tmp_dct['exp_date'],'%m/%d/%Y').replace(hour=0, minute=0, second=0, microsecond=0)                         #check for empty/null/blank values and replace with default date
        output_lst.append(tmp_dct)
    except:
        pass


print(output_lst)

这样更有效，因为您只循环一次。