{"id":1173667,"date":"2025-01-15T17:06:22","date_gmt":"2025-01-15T09:06:22","guid":{"rendered":"https:\/\/docs.pingcode.com\/ask\/ask-ask\/1173667.html"},"modified":"2025-01-15T17:06:27","modified_gmt":"2025-01-15T09:06:27","slug":"python%e4%b8%ad%e7%9a%84%e7%a9%ba%e5%a6%82%e4%bd%95%e8%a1%a8%e7%a4%ba","status":"publish","type":"post","link":"https:\/\/docs.pingcode.com\/ask\/1173667.html","title":{"rendered":"python\u4e2d\u7684\u7a7a\u5982\u4f55\u8868\u793a"},"content":{"rendered":"

\"python\u4e2d\u7684\u7a7a\u5982\u4f55\u8868\u793a\"<\/p>\n

\u5728Python\u4e2d\uff0c\u7a7a\u7684\u8868\u793a\u65b9\u5f0f\u5305\u62ec None\u3001\u7a7a\u5b57\u7b26\u4e32\uff08""\uff09\u3001\u7a7a\u5217\u8868\uff08[]\uff09\u3001\u7a7a\u5b57\u5178\uff08{}\uff09\u3001\u7a7a\u5143\u7ec4\uff08()\uff09<\/strong> \u7b49\u3002\u5176\u4e2d\uff0c\u6700\u5e38\u7528\u7684\u662fNone<\/strong>\u3002None \u662fPython\u5185\u7f6e\u7684\u4e00\u4e2a\u5e38\u91cf\uff0c\u8868\u793a\u7a7a\u503c\u6216\u65e0\u503c\u7684\u5bf9\u8c61\u3002\u4e0e\u5176\u4ed6\u8bed\u8a00\u4e2d\u7684null\u6216nil\u7c7b\u4f3c\u3002None\u901a\u5e38\u7528\u4e8e\u51fd\u6570\u6ca1\u6709\u8fd4\u56de\u503c\u65f6\u7684\u9ed8\u8ba4\u8fd4\u56de\u503c\u3001\u53d8\u91cf\u521d\u59cb\u5316\u3001\u5360\u4f4d\u7b26\u7b49\u60c5\u51b5\u3002<\/p>\n<\/p>\n

\u4e00\u3001None\u7684\u4f7f\u7528<\/h3>\n<\/p>\n

None<\/strong> \u662f Python \u4e2d\u552f\u4e00\u7684 NoneType \u7c7b\u578b\u5bf9\u8c61\uff0c\u5e38\u7528\u4e8e\u8868\u793a\u53d8\u91cf\u6ca1\u6709\u5b9e\u9645\u503c\u3002\u4e0b\u9762\u8be6\u7ec6\u4ecb\u7ecd None \u7684\u4f7f\u7528\u573a\u666f\u53ca\u6ce8\u610f\u4e8b\u9879\u3002<\/p>\n<\/p>\n

1\u3001\u53d8\u91cf\u521d\u59cb\u5316<\/h4>\n<\/p>\n

\u5728\u5f88\u591a\u60c5\u51b5\u4e0b\uff0c\u6211\u4eec\u9700\u8981\u5148\u58f0\u660e\u4e00\u4e2a\u53d8\u91cf\u4f46\u5e76\u4e0d\u8d4b\u4e88\u5176\u5b9e\u9645\u503c\u3002\u8fd9\u65f6\u53ef\u4ee5\u4f7f\u7528 None \u6765\u8fdb\u884c\u521d\u59cb\u5316\u3002<\/p>\n<\/p>\n

my_var = None<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u8fd9\u6837\u505a\u7684\u597d\u5904\u662f\u53ef\u4ee5\u660e\u786e\u8868\u793a\u6b64\u53d8\u91cf\u76ee\u524d\u6ca1\u6709\u6709\u6548\u503c\uff0c\u800c\u4e0d\u662f\u8bef\u7528\u7a7a\u5b57\u7b26\u4e32\u6216\u5176\u4ed6\u7c7b\u578b\u7684\u7a7a\u503c\u3002<\/p>\n<\/p>\n
2\u3001\u51fd\u6570\u65e0\u8fd4\u56de\u503c<\/h4>\n<\/p>\n
\u5728 Python \u4e2d\uff0c\u5982\u679c\u4e00\u4e2a\u51fd\u6570\u6ca1\u6709\u663e\u5f0f\u5730\u8fd4\u56de\u503c\uff0c\u9ed8\u8ba4\u4f1a\u8fd4\u56de None\u3002<\/p>\n<\/p>\n
def my_function():<\/p>\n
    pass<\/p>\n
result = my_function()<\/p>\n
print(result)  # \u8f93\u51fa: None<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u8fd9\u5728\u51fd\u6570\u8bbe\u8ba1\u4e2d\u5f88\u5e38\u89c1\uff0c\u5c24\u5176\u662f\u90a3\u4e9b\u4e3b\u8981\u7528\u4e8e\u6267\u884c\u67d0\u4e9b\u52a8\u4f5c\u800c\u4e0d\u9700\u8981\u8fd4\u56de\u7ed3\u679c\u7684\u51fd\u6570\u3002<\/p>\n<\/p>\n
3\u3001\u5360\u4f4d\u7b26<\/h4>\n<\/p>\n
\u5728\u67d0\u4e9b\u6570\u636e\u7ed3\u6784\u5982\u5217\u8868\u6216\u5b57\u5178\u4e2d\uff0c\u6211\u4eec\u53ef\u80fd\u9700\u8981\u6682\u65f6\u5360\u7528\u4e00\u4e2a\u4f4d\u7f6e\u4f46\u4e0d\u8d4b\u4e88\u5b9e\u9645\u503c\uff0c\u8fd9\u65f6\u53ef\u4ee5\u4f7f\u7528 None \u4f5c\u4e3a\u5360\u4f4d\u7b26\u3002<\/p>\n<\/p>\n
my_list = [1, 2, None, 4]<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u8fd9\u6837\u53ef\u4ee5\u5728\u540e\u7eed\u5904\u7406\u4e2d\u6839\u636e\u9700\u8981\u66ff\u6362 None \u4e3a\u5b9e\u9645\u503c\u3002<\/p>\n<\/p>\n
\u4e8c\u3001\u7a7a\u5b57\u7b26\u4e32\u7684\u4f7f\u7528<\/h3>\n<\/p>\n
\u7a7a\u5b57\u7b26\u4e32\uff08""\uff09<\/strong> \u5728 Python \u4e2d\u662f\u4e00\u4e2a\u957f\u5ea6\u4e3a\u96f6\u7684\u5b57\u7b26\u4e32\u5bf9\u8c61\uff0c\u5e38\u7528\u4e8e\u8868\u793a\u6587\u672c\u6570\u636e\u7684\u7a7a\u503c\u3002<\/p>\n<\/p>\n
1\u3001\u5b57\u7b26\u4e32\u521d\u59cb\u5316<\/h4>\n<\/p>\n
\u6709\u65f6\u6211\u4eec\u9700\u8981\u58f0\u660e\u4e00\u4e2a\u5b57\u7b26\u4e32\u53d8\u91cf\u4f46\u6682\u65f6\u4e0d\u8d4b\u4e88\u5176\u5b9e\u9645\u5185\u5bb9\uff0c\u8fd9\u65f6\u53ef\u4ee5\u4f7f\u7528\u7a7a\u5b57\u7b26\u4e32\u3002<\/p>\n<\/p>\n
empty_string = ""<\/p>\n
<\/code><\/pre>\n<\/p>\n
2\u3001\u5b57\u7b26\u4e32\u8fde\u63a5<\/h4>\n<\/p>\n
\u5728\u5904\u7406\u5b57\u7b26\u4e32\u8fde\u63a5\u65f6\uff0c\u7a7a\u5b57\u7b26\u4e32\u4e5f\u662f\u975e\u5e38\u6709\u7528\u7684\u5de5\u5177\u3002<\/p>\n<\/p>\n
str1 = "Hello"<\/p>\n
str2 = ""<\/p>\n
result = str1 + str2 + " World"<\/p>\n
print(result)  # \u8f93\u51fa: Hello World<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u4e09\u3001\u7a7a\u5217\u8868\u7684\u4f7f\u7528<\/h3>\n<\/p>\n
\u7a7a\u5217\u8868\uff08[]\uff09<\/strong> \u662f\u4e00\u4e2a\u6ca1\u6709\u5143\u7d20\u7684\u5217\u8868\u5bf9\u8c61\uff0c\u5e38\u7528\u4e8e\u8868\u793a\u96c6\u5408\u6570\u636e\u7684\u7a7a\u503c\u3002<\/p>\n<\/p>\n
1\u3001\u5217\u8868\u521d\u59cb\u5316<\/h4>\n<\/p>\n
\u5728\u9700\u8981\u58f0\u660e\u4e00\u4e2a\u5217\u8868\u4f46\u6682\u65f6\u4e0d\u653e\u5165\u4efb\u4f55\u5143\u7d20\u65f6\uff0c\u53ef\u4ee5\u4f7f\u7528\u7a7a\u5217\u8868\u3002<\/p>\n<\/p>\n
empty_list = []<\/p>\n
<\/code><\/pre>\n<\/p>\n
2\u3001\u5217\u8868\u6269\u5c55<\/h4>\n<\/p>\n
\u901a\u8fc7\u6dfb\u52a0\u5143\u7d20\uff0c\u53ef\u4ee5\u9010\u6b65\u6269\u5c55\u7a7a\u5217\u8868\u3002<\/p>\n<\/p>\n
empty_list.append(1)<\/p>\n
empty_list.append(2)<\/p>\n
print(empty_list)  # \u8f93\u51fa: [1, 2]<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u56db\u3001\u7a7a\u5b57\u5178\u7684\u4f7f\u7528<\/h3>\n<\/p>\n
\u7a7a\u5b57\u5178\uff08{}\uff09<\/strong> \u662f\u4e00\u4e2a\u6ca1\u6709\u952e\u503c\u5bf9\u7684\u5b57\u5178\u5bf9\u8c61\uff0c\u5e38\u7528\u4e8e\u8868\u793a\u6620\u5c04\u6570\u636e\u7684\u7a7a\u503c\u3002<\/p>\n<\/p>\n
1\u3001\u5b57\u5178\u521d\u59cb\u5316<\/h4>\n<\/p>\n
\u5728\u9700\u8981\u58f0\u660e\u4e00\u4e2a\u5b57\u5178\u4f46\u6682\u65f6\u4e0d\u653e\u5165\u4efb\u4f55\u952e\u503c\u5bf9\u65f6\uff0c\u53ef\u4ee5\u4f7f\u7528\u7a7a\u5b57\u5178\u3002<\/p>\n<\/p>\n
empty_dict = {}<\/p>\n
<\/code><\/pre>\n<\/p>\n
2\u3001\u5b57\u5178\u6269\u5c55<\/h4>\n<\/p>\n
\u901a\u8fc7\u6dfb\u52a0\u952e\u503c\u5bf9\uff0c\u53ef\u4ee5\u9010\u6b65\u6269\u5c55\u7a7a\u5b57\u5178\u3002<\/p>\n<\/p>\n
empty_dict['key1'] = 'value1'<\/p>\n
empty_dict['key2'] = 'value2'<\/p>\n
print(empty_dict)  # \u8f93\u51fa: {'key1': 'value1', 'key2': 'value2'}<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u4e94\u3001\u7a7a\u5143\u7ec4\u7684\u4f7f\u7528<\/h3>\n<\/p>\n
\u7a7a\u5143\u7ec4\uff08()\uff09<\/strong> \u662f\u4e00\u4e2a\u6ca1\u6709\u5143\u7d20\u7684\u5143\u7ec4\u5bf9\u8c61\uff0c\u5e38\u7528\u4e8e\u8868\u793a\u4e0d\u53ef\u53d8\u96c6\u5408\u6570\u636e\u7684\u7a7a\u503c\u3002<\/p>\n<\/p>\n
1\u3001\u5143\u7ec4\u521d\u59cb\u5316<\/h4>\n<\/p>\n
\u5728\u9700\u8981\u58f0\u660e\u4e00\u4e2a\u5143\u7ec4\u4f46\u6682\u65f6\u4e0d\u653e\u5165\u4efb\u4f55\u5143\u7d20\u65f6\uff0c\u53ef\u4ee5\u4f7f\u7528\u7a7a\u5143\u7ec4\u3002<\/p>\n<\/p>\n
empty_tuple = ()<\/p>\n
<\/code><\/pre>\n<\/p>\n
2\u3001\u5143\u7ec4\u64cd\u4f5c<\/h4>\n<\/p>\n
\u7531\u4e8e\u5143\u7ec4\u662f\u4e0d\u53ef\u53d8\u7684\uff0c\u4e0d\u80fd\u50cf\u5217\u8868\u90a3\u6837\u9010\u6b65\u6dfb\u52a0\u5143\u7d20\uff0c\u4f46\u53ef\u4ee5\u901a\u8fc7\u8fde\u63a5\u64cd\u4f5c\u521b\u5efa\u65b0\u7684\u5143\u7ec4\u3002<\/p>\n<\/p>\n
new_tuple = empty_tuple + (1, 2, 3)<\/p>\n
print(new_tuple)  # \u8f93\u51fa: (1, 2, 3)<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u516d\u3001\u7a7a\u503c\u7684\u5224\u65ad<\/h3>\n<\/p>\n
\u5728\u5b9e\u9645\u7f16\u7a0b\u4e2d\uff0c\u6211\u4eec\u7ecf\u5e38\u9700\u8981\u5224\u65ad\u4e00\u4e2a\u53d8\u91cf\u662f\u5426\u4e3a\u7a7a\u3002Python \u63d0\u4f9b\u4e86\u4e00\u4e9b\u4fbf\u6377\u7684\u65b9\u6cd5\u6765\u8fdb\u884c\u7a7a\u503c\u5224\u65ad\u3002<\/p>\n<\/p>\n
1\u3001\u4f7f\u7528 is \u5173\u952e\u5b57<\/h4>\n<\/p>\n
\u5bf9\u4e8e None \u503c\u7684\u5224\u65ad\uff0c\u63a8\u8350\u4f7f\u7528 is \u5173\u952e\u5b57\u3002<\/p>\n<\/p>\n
if my_var is None:<\/p>\n
    print("my_var \u662f None")<\/p>\n
<\/code><\/pre>\n<\/p>\n
2\u3001\u4f7f\u7528 not \u8fd0\u7b97\u7b26<\/h4>\n<\/p>\n
\u5bf9\u4e8e\u7a7a\u5b57\u7b26\u4e32\u3001\u7a7a\u5217\u8868\u3001\u7a7a\u5b57\u5178\u3001\u7a7a\u5143\u7ec4\u7b49\uff0c\u53ef\u4ee5\u4f7f\u7528 not \u8fd0\u7b97\u7b26\u8fdb\u884c\u5224\u65ad\u3002<\/p>\n<\/p>\n
if not empty_string:<\/p>\n
    print("empty_string \u662f\u7a7a\u5b57\u7b26\u4e32")<\/p>\n
if not empty_list:<\/p>\n
    print("empty_list \u662f\u7a7a\u5217\u8868")<\/p>\n
if not empty_dict:<\/p>\n
    print("empty_dict \u662f\u7a7a\u5b57\u5178")<\/p>\n
if not empty_tuple:<\/p>\n
    print("empty_tuple \u662f\u7a7a\u5143\u7ec4")<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u4e03\u3001\u7a7a\u503c\u7684\u5904\u7406<\/h3>\n<\/p>\n
\u5904\u7406\u7a7a\u503c\u662f\u7f16\u7a0b\u4e2d\u5e38\u89c1\u7684\u4efb\u52a1\uff0c\u5408\u7406\u7684\u5904\u7406\u65b9\u5f0f\u53ef\u4ee5\u63d0\u9ad8\u7a0b\u5e8f\u7684\u5065\u58ee\u6027\u548c\u53ef\u8bfb\u6027\u3002<\/p>\n<\/p>\n
1\u3001\u63d0\u4f9b\u9ed8\u8ba4\u503c<\/h4>\n<\/p>\n
\u5728\u51fd\u6570\u6216\u65b9\u6cd5\u4e2d\uff0c\u53ef\u4ee5\u4e3a\u53c2\u6570\u63d0\u4f9b\u9ed8\u8ba4\u503c\u6765\u907f\u514d\u7a7a\u503c\u5e26\u6765\u7684\u95ee\u9898\u3002<\/p>\n<\/p>\n
def greet(name=None):<\/p>\n
    if name is None:<\/p>\n
        name = "Guest"<\/p>\n
    print(f"Hello, {name}!")<\/p>\n
greet()  # \u8f93\u51fa: Hello, Guest!<\/p>\n
greet("Alice")  # \u8f93\u51fa: Hello, Alice!<\/p>\n
<\/code><\/pre>\n<\/p>\n
2\u3001\u4f7f\u7528 try-except \u5904\u7406\u5f02\u5e38<\/h4>\n<\/p>\n
\u5728\u5904\u7406\u53ef\u80fd\u51fa\u73b0\u7a7a\u503c\u7684\u4ee3\u7801\u5757\u65f6\uff0c\u53ef\u4ee5\u4f7f\u7528 try-except \u8bed\u53e5\u6765\u6355\u83b7\u5e76\u5904\u7406\u5f02\u5e38\u3002<\/p>\n<\/p>\n
try:<\/p>\n
    result = some_function()<\/p>\n
    if result is None:<\/p>\n
        rAI<\/a>se ValueError("\u7ed3\u679c\u4e0d\u80fd\u4e3a\u7a7a")<\/p>\n
except ValueError as e:<\/p>\n
    print(e)<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u516b\u3001\u7a7a\u503c\u7684\u5e94\u7528\u573a\u666f<\/h3>\n<\/p>\n
\u7a7a\u503c\u5728\u5b9e\u9645\u5e94\u7528\u4e2d\u6709\u5f88\u591a\u573a\u666f\uff0c\u4e86\u89e3\u8fd9\u4e9b\u573a\u666f\u6709\u52a9\u4e8e\u66f4\u597d\u5730\u7406\u89e3\u548c\u4f7f\u7528\u7a7a\u503c\u3002<\/p>\n<\/p>\n
1\u3001\u6570\u636e\u5e93\u67e5\u8be2<\/h4>\n<\/p>\n
\u5728\u8fdb\u884c\u6570\u636e\u5e93\u67e5\u8be2\u65f6\uff0c\u53ef\u80fd\u4f1a\u9047\u5230\u67e5\u8be2\u7ed3\u679c\u4e3a\u7a7a\u7684\u60c5\u51b5\u3002\u6b64\u65f6\u53ef\u4ee5\u4f7f\u7528 None \u6216\u7a7a\u5217\u8868\u7b49\u6765\u8868\u793a\u67e5\u8be2\u7ed3\u679c\u4e3a\u7a7a\u3002<\/p>\n<\/p>\n
def fetch_data(query):<\/p>\n
    data = execute_query(query)<\/p>\n
    if not data:<\/p>\n
        return None<\/p>\n
    return data<\/p>\n
result = fetch_data("SELECT * FROM table")<\/p>\n
if result is None:<\/p>\n
    print("\u67e5\u8be2\u7ed3\u679c\u4e3a\u7a7a")<\/p>\n
<\/code><\/pre>\n<\/p>\n
2\u3001\u6587\u4ef6\u64cd\u4f5c<\/h4>\n<\/p>\n
\u5728\u8fdb\u884c\u6587\u4ef6\u64cd\u4f5c\u65f6\uff0c\u53ef\u80fd\u4f1a\u9047\u5230\u6587\u4ef6\u5185\u5bb9\u4e3a\u7a7a\u7684\u60c5\u51b5\u3002\u6b64\u65f6\u53ef\u4ee5\u4f7f\u7528\u7a7a\u5b57\u7b26\u4e32\u6216 None \u6765\u8868\u793a\u6587\u4ef6\u5185\u5bb9\u4e3a\u7a7a\u3002<\/p>\n<\/p>\n
def read_file(file_path):<\/p>\n
    with open(file_path, 'r') as file:<\/p>\n
        content = file.read()<\/p>\n
        if not content:<\/p>\n
            return None<\/p>\n
        return content<\/p>\n
file_content = read_file("example.txt")<\/p>\n
if file_content is None:<\/p>\n
    print("\u6587\u4ef6\u5185\u5bb9\u4e3a\u7a7a")<\/p>\n
<\/code><\/pre>\n<\/p>\n
3\u3001API \u8c03\u7528<\/h4>\n<\/p>\n
\u5728\u8fdb\u884c API \u8c03\u7528\u65f6\uff0c\u53ef\u80fd\u4f1a\u9047\u5230\u54cd\u5e94\u6570\u636e\u4e3a\u7a7a\u7684\u60c5\u51b5\u3002\u6b64\u65f6\u53ef\u4ee5\u4f7f\u7528 None \u6216\u7a7a\u5b57\u5178\u7b49\u6765\u8868\u793a\u54cd\u5e94\u6570\u636e\u4e3a\u7a7a\u3002<\/p>\n<\/p>\n
def fetch_api_data(url):<\/p>\n
    response = requests.get(url)<\/p>\n
    if response.status_code != 200:<\/p>\n
        return None<\/p>\n
    data = response.json()<\/p>\n
    if not data:<\/p>\n
        return None<\/p>\n
    return data<\/p>\n
api_data = fetch_api_data("https:\/\/api.example.com\/data")<\/p>\n
if api_data is None:<\/p>\n
    print("API \u54cd\u5e94\u6570\u636e\u4e3a\u7a7a")<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u4e5d\u3001\u603b\u7ed3<\/h3>\n<\/p>\n
\u5728 Python \u4e2d\uff0c\u7a7a\u503c\u7684\u8868\u793a\u65b9\u5f0f\u6709\u591a\u79cd\uff0c\u5305\u62ec None\u3001\u7a7a\u5b57\u7b26\u4e32\u3001\u7a7a\u5217\u8868\u3001\u7a7a\u5b57\u5178\u3001\u7a7a\u5143\u7ec4\u7b49\u3002\u5176\u4e2d\uff0cNone \u662f\u6700\u5e38\u7528\u7684\u7a7a\u503c\u8868\u793a\u65b9\u5f0f<\/strong>\u3002\u4e86\u89e3\u548c\u638c\u63e1\u8fd9\u4e9b\u7a7a\u503c\u7684\u4f7f\u7528\u65b9\u6cd5\u548c\u5e94\u7528\u573a\u666f\uff0c\u5bf9\u4e8e\u7f16\u5199\u5065\u58ee\u3001\u9ad8\u6548\u7684 Python \u4ee3\u7801\u81f3\u5173\u91cd\u8981\u3002\u5408\u7406\u5730\u4f7f\u7528\u7a7a\u503c\u53ef\u4ee5\u63d0\u9ad8\u4ee3\u7801\u7684\u53ef\u8bfb\u6027\u548c\u53ef\u7ef4\u62a4\u6027\uff0c\u907f\u514d\u56e0\u7a7a\u503c\u5904\u7406\u4e0d\u5f53\u800c\u5bfc\u81f4\u7684\u9519\u8bef\u548c\u5f02\u5e38\u3002<\/p>\n<\/p>\n
\u76f8\u5173\u95ee\u7b54FAQs\uff1a<\/strong><\/h2>\n
 \u5728Python\u4e2d\uff0c\u5982\u4f55\u8868\u793a\u4e00\u4e2a\u7a7a\u503c\u6216\u7a7a\u5bf9\u8c61\uff1f<\/strong>
\u5728Python\u4e2d\uff0c\u53ef\u4ee5\u4f7f\u7528None<\/code>\u6765\u8868\u793a\u4e00\u4e2a\u7a7a\u503c\u3002None<\/code>\u662f\u4e00\u4e2a\u7279\u6b8a\u7684\u5e38\u91cf\uff0c\u8868\u793a\u6ca1\u6709\u503c\u6216\u7a7a\u5bf9\u8c61\u3002\u6b64\u5916\uff0c\u7a7a\u5b57\u7b26\u4e32""<\/code>\u3001\u7a7a\u5217\u8868[]<\/code>\u3001\u7a7a\u5b57\u5178{}<\/code>\u548c\u7a7a\u5143\u7ec4() <\/code>\u4e5f\u53ef\u4ee5\u7528\u6765\u8868\u793a\u4e0d\u540c\u7c7b\u578b\u7684\u7a7a\u5bf9\u8c61\u3002<\/p>\n
\u5982\u4f55\u5224\u65ad\u4e00\u4e2a\u53d8\u91cf\u662f\u5426\u4e3a\u7a7a\uff1f<\/strong>
\u53ef\u4ee5\u4f7f\u7528is<\/code>\u8fd0\u7b97\u7b26\u6765\u5224\u65ad\u4e00\u4e2a\u53d8\u91cf\u662f\u5426\u662fNone<\/code>\uff0c\u4f8b\u5982\uff1aif my_variable is None:<\/code>\u3002\u5bf9\u4e8e\u5176\u4ed6\u7c7b\u578b\u7684\u7a7a\u5bf9\u8c61\uff0c\u53ef\u4ee5\u76f4\u63a5\u4f7f\u7528\u6761\u4ef6\u5224\u65ad\uff0c\u56e0\u4e3a\u7a7a\u5bf9\u8c61\u5728\u5e03\u5c14\u4e0a\u4e0b\u6587\u4e2d\u4f1a\u88ab\u89c6\u4e3aFalse<\/code>\uff0c\u4f8b\u5982\uff1aif not my_list:<\/code>\u53ef\u4ee5\u7528\u6765\u68c0\u67e5\u4e00\u4e2a\u5217\u8868\u662f\u5426\u4e3a\u7a7a\u3002<\/p>\n
\u5728Python\u4e2d\uff0c\u6709\u54ea\u4e9b\u5e38\u89c1\u7684\u7a7a\u5bf9\u8c61\u5e94\u7528\u573a\u666f\uff1f<\/strong>
\u7a7a\u5bf9\u8c61\u5728\u591a\u79cd\u60c5\u51b5\u4e0b\u975e\u5e38\u6709\u7528\uff0c\u4f8b\u5982\u5728\u51fd\u6570\u4e2d\u4f5c\u4e3a\u9ed8\u8ba4\u53c2\u6570\u3001\u521d\u59cb\u5316\u53d8\u91cf\u4ee5\u907f\u514d\u5f15\u7528\u9519\u8bef\u3001\u5728\u6570\u636e\u5904\u7406\u65f6\u6807\u8bc6\u7f3a\u5931\u503c\u7b49\u3002\u4f7f\u7528\u7a7a\u5bf9\u8c61\u53ef\u4ee5\u63d0\u9ad8\u4ee3\u7801\u7684\u53ef\u8bfb\u6027\u548c\u5b89\u5168\u6027\uff0c\u907f\u514d\u4e86\u4e0d\u5fc5\u8981\u7684\u9519\u8bef\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"\u5728Python\u4e2d\uff0c\u7a7a\u7684\u8868\u793a\u65b9\u5f0f\u5305\u62ec None\u3001\u7a7a\u5b57\u7b26\u4e32\uff08""\uff09\u3001\u7a7a\u5217\u8868\uff08[]\uff09\u3001\u7a7a\u5b57\u5178\uff08{ […]","protected":false},"author":3,"featured_media":1173685,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[37],"tags":[],"acf":[],"_links":{"self":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts\/1173667"}],"collection":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/comments?post=1173667"}],"version-history":[{"count":"1","href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts\/1173667\/revisions"}],"predecessor-version":[{"id":1173686,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts\/1173667\/revisions\/1173686"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/media\/1173685"}],"wp:attachment":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/media?parent=1173667"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/categories?post=1173667"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/tags?post=1173667"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}