如何在Python中实现优雅错误处理？以Selenium爬LinkedIn为例

我正在使用Selenium爬取LinkedIn，这项任务稳定性极差，经常抛出异常。我希望找到一种优雅的错误处理方式，网上常见的try-catch写法过于繁琐。现有代码如下：

try:
    WebDriverWait(driver, 20).until(EC.element_to_be_clickable(job))
    job_title = job.find_element(By.CLASS_NAME, "base-search-card__title").text
    company = job.find_element(By.CLASS_NAME, "base-search-card__subtitle").text
    location = job.find_element(By.CLASS_NAME, "job-search-card__location").text
except :
    print("Boom Boom")

若任意一个find_element方法抛出异常，整个try块就会停止执行并进入except分支。我希望实现单个元素提取失败时仅返回空字符串，而不触发全局的except。我尝试过将每个提取逻辑封装成函数，示例如下：

def extract_job_title(job):
    try:
        return job.find_element(By.CLASS_NAME, "base-search-card__title").text
    except:
        return ""

然后通过job_title = extract_job_title(job)调用，但这种方式依然繁琐。我想要类似Swift中的简洁写法，例如：

let job_title = try? job.find_element(By.CLASS_NAME, "base-search-card__title").text ?? ""

请问Python中是否有类似的语法？如果没有，有没有其他更优雅的实现方式？

Python没有Swift那种try?+空合运算符的原生语法，但可以通过以下几种简洁方式实现需求：

1. 通用提取函数 #

不用为每个元素单独写函数，封装一个通用的提取逻辑：

def extract_text(element, by, value, default=""):
    try:
        return element.find_element(by, value).text
    except Exception:
        return default

调用时只需传入定位参数，代码简洁直观：

WebDriverWait(driver, 20).until(EC.element_to_be_clickable(job))
job_title = extract_text(job, By.CLASS_NAME, "base-search-card__title")
company = extract_text(job, By.CLASS_NAME, "base-search-card__subtitle")
location = extract_text(job, By.CLASS_NAME, "job-search-card__location")

2. 利用find_elements特性 #

find_elements找不到元素时返回空列表，不会抛出异常，结合三元表达式可以简化代码：

job_title = job.find_elements(By.CLASS_NAME, "base-search-card__title")[0].text if job.find_elements(By.CLASS_NAME, "base-search-card__title") else ""
company = job.find_elements(By.CLASS_NAME, "base-search-card__subtitle")[0].text if job.find_elements(By.CLASS_NAME, "base-search-card__subtitle") else ""
location = job.find_elements(By.CLASS_NAME, "job-search-card__location")[0].text if job.find_elements(By.CLASS_NAME, "job-search-card__location") else ""

嫌三元表达式长的话，可以封装成lambda：

get_text = lambda elem, by, val: elem.find_elements(by, val)[0].text if elem.find_elements(by, val) else ""

job_title = get_text(job, By.CLASS_NAME, "base-search-card__title")
company = get_text(job, By.CLASS_NAME, "base-search-card__subtitle")

3. 海象运算符优化（Python 3.8+） #

用海象运算符避免重复调用find_elements，提升效率：

job_title = elems[0].text if (elems := job.find_elements(By.CLASS_NAME, "base-search-card__title")) else ""
company = elems[0].text if (elems := job.find_elements(By.CLASS_NAME, "base-search-card__subtitle")) else ""
location = elems[0].text if (elems := job.find_elements(By.CLASS_NAME, "job-search-card__location")) else ""

4. 装饰器实现通用捕获（进阶） #

如果需要更灵活的默认值配置，可以写一个装饰器：

def catch_default(default=""):
    def decorator(func):
        def wrapper(*args, **kwargs):
            try:
                return func(*args, **kwargs)
            except Exception:
                return default
        return wrapper
    return decorator

使用方式：

# 定义提取函数
@catch_default()
def get_job_title(job):
    return job.find_element(By.CLASS_NAME, "base-search-card__title").text

job_title = get_job_title(job)

# 或者直接包裹lambda
company = catch_default()(lambda job: job.find_element(By.CLASS_NAME, "base-search-card__subtitle").text)(job)

内容的提问来源于stack exchange，提问作者user19231332