如何迭代 Python 中的字节对象？

Question

我正在 Django 中做一个 POST 请求，我正在接收一个字节对象。 我需要计算特定用户出现在此对象上的次数，但我收到以下错误TypeError: 'int' object is not subscriptable 。 这是我到目前为止：

def filter_url(user):
    ''' do the POST request, this code works '''

    filters = {"filter": {
    "filters": [{
        "field": "Issue_Status",
        "operator": "neq",
        "value": "Queued"
    }],
    "logic": "and"}}

    url = "http://10.61.202.98:8081/Dev/api/rows/cat/tickets?"
    response = requests.post(url, json=filters)
    return response

def request_count():
    '''This code requests a POST method and then it stores the result of all the data 
    for user001 as a bytes object in the response variable. Afterwards, a call to the 
    perform_count function is made to count the number of times that user user001 appeared.'''

    user = "user001"
    response = filter_url(user).text.encode('utf-8')
    weeks_of_data = []     
    weeks_of_data.append(perform_count(response))

def perform_count(response):
    ''' This code does not work, int object is not subscriptable '''
    return Counter([k['user_id'] for k in response)

#structure of the bytes object
b'[{"id":1018002,"user_id":"user001","registered_first_time":"Yes", ...}]'

# This is the result that indicates that response is a bytes object.
print(type(response))
<class 'bytes'>

如何使用 peform_count() 函数计算 user001 出现的次数？ 此功能需要进行哪些修改才能工作？

Answer 1

您确实收到了字节，是的，但是您让requests库对其进行解码（通过response.text属性，它会自动对数据进行解码），然后您自己重新编码：

response = filter_url(user).text.encode('utf-8')

除了仅使用response.content属性来避免解码 -> 编码往返之外，您实际上应该将数据解码为 JSON ：

data = filter_url(user).json()

现在data是一个字典列表，您的perform_count()函数可以直接对其进行操作。