python - 如何减少到一次尝试，除了声明

Question

我有一个包含多个 try-except 语句的字典。我尝试使用 r.get() 检索值，但它向我抛出一个 NoneObject 类型错误。我知道 .get() 的默认参数是 None，但它不起作用。我有多个列表，我在每次迭代时附加来自不同字典值的数据。

如何将代码缩减为单个 try-except 语句？谢谢!

这是我的代码:

for num in issue_number:
    print(num)
    Response = requests.get(f'https://example.com/rest/api/2/issue/Proj-{num}?expand=changelog&maxResults =1000', auth=(example))
    r = Response.json()
    try:
        task_list.append(r['key'])
    except TypeError:
        task_list.append('NA')
    try:
        summary_list.append(r['fields']['summary'])
    except TypeError:
        summary_list.append('NA')
    try:
        assignee_list.append(r['fields']['assignee']['displayName'])
    except TypeError:
        assignee_list.append('NA')
    try:
        created_list.append(r['fields']['created'])
    except:
        created_list.append('NA')
    try:
        status_list.append(r['fields']['status']['name'])
    except:
        status_list.append('NA')
    try:
        due_date_list.append(r['fields']['duedate'])
    except:
        due_date_list.append('NA')
    try:
        resolution_list.append(r['fields']['resolution']['name'])
    except:
        resolution_list.append('NA')
    try:
        resolution_date_list.append(r['fields']['resolutiondate'])
    except:
        resolution_date_list.append('NA')

Answer 1

您可以通过链接多个 get 调用来避免所有这些:

for num in issue_number:
    print(num)
    Response = requests.get(f'https://example.com/rest/api/2/issue/Proj-{num}?expand=changelog&maxResults =1000', auth=(example))
    r = Response.json()
    task_list.append(r.get('key', 'NA'))
    summary_list.append(r.get('fields', {}).get('summary', 'NA'))
    assignee_list.append(r.get('fields', {}).get('assignee', {}).get('displayName','NA'))
    created_list.append(r.get('fields', {}).get('created', 'NA'))
    status_list.append(r.get('fields', {}).get('status', {}).get('name', 'NA'))
    due_date_list.append(r.get('fields', {}).get('duedate', 'NA'))
    resolution_list.append(r.get('fields', {}).get('resolution', {}).get('name', 'NA'))
    resolution_date_list.append(r.get('fields', {}).get('resolutiondate', 'NA'))

但是，由于您多次执行相同的操作，因此您可能会发现使用函数更方便，例如:

def get_deep(d, *keys, default=None):
    for k in keys:
        if not d or k not in d:
            # Stop early if a key is not found
            return default
        d = d[k]
    return d if d is not None else default

# ...

for num in issue_number:
    print(num)
    Response = requests.get(f'https://example.com/rest/api/2/issue/Proj-{num}?expand=changelog&maxResults =1000', auth=(example))
    r = Response.json()
    task_list.append(get_deep(r, 'key', default='NA'))
    summary_list.append(get_deep(r, 'fields', 'summary', default='NA'))
    assignee_list.append(get_deep(r, 'fields', 'assignee', 'displayName', default='NA'))
    created_list.append(get_deep(r, 'fields', 'created', default='NA'))
    status_list.append(get_deep(r, 'fields', 'status', 'name', default='NA'))
    due_date_list.append(get_deep(r, 'fields', 'duedate', default='NA'))
    resolution_list.append(get_deep(r, 'fields', 'resolution', 'name', default='NA'))
    resolution_date_list.append(get_deep(r, 'fields', 'resolutiondate', default='NA'))