当 Python 正在写入 CSV 时，脚本会在 csv 文件的 try / except 块中插入新行

Question

美好的一天，

我是 Python 和 Selenium 的新手，需要帮助解决以下问题：

我的代码片段如下：

num_page_items = len(date)
blank = "0"
try:
    with open('results.csv', 'a') as f:
        for i in range(num_page_items):
            f.write(name[i].text + "#" + surname[i].text + "#" + ref[i].text + "#" + url[i].text + "\n")
except IndexError:
    with open('results.csv', 'a') as f:
            f.write(blank)

我有一些变量正在使用 selenium 抓取网站。数据示例和预期输出如下：

Name: Joe Surname: Soap Ref: 1234 URL: www.example.com

Name: Bill Surname: Smith Ref: 4567 URL: www.dot.com

expected output

当所有元素都存在时，Python 脚本运行良好，但是当一个元素（在示例中：第二个条目中不存在 Ref）不存在时，输出如下

output when an element doesn't exist

如果网页上不存在该变量，我该怎么做才能将变量设置为 "Null"，因此预期的新输出如下：

expected output when element doesn't exist

Just as a side note, the error I receive isn't a Selenium exception, but is an IndexError, hence the use of the "IndexError" except statement

编辑 - Felipe Gutierrez 的建议

Felipe 建议的更大的代码片段：

for url in links:
        driver.get(url) #goes to the array and opens each link

        company = driver.find_elements_by_xpath("""//*[contains(@id, 'node')]/div[2]/ul/li/div/div[1]/span""") 
        date = driver.find_elements_by_xpath("""//*[contains(@id, 'node')]/div[1]/div[1]/div[2]/div/span""")
        ref = driver.find_elements_by_xpath("""//*[contains(@id, 'node')]/div[1]/div[3]""")
        title = driver.find_elements_by_xpath("""//*[@id="page-title"]/span""")
        urlinf = driver.current_url

        num_page_items = len(date)
        blank = "blank"

        for ref in ref:
            if ref is None:
                ref = 0

        with open('results.csv', 'a') as f:
            for i in range(num_page_items):
                f.write(company[i].text + "#" + date[i].text + "#" + ref[i].text + "#" + title[i].text + "#" + urlinf + "\n")

driver.close()

我现在收到以下错误：

Traceback (most recent call last): File "accc_for_loop_nest.py", line 50, in f.write(company[i].text + "#" + date[i].text + "#" + ref[i].text + "#" + title[i].text + "#" + urlinf + "\n") TypeError: 'WebElement' object does not support indexing

Answer 1

您丢失了正在使用 try-catch 迭代的列表的索引，您可以尝试在插入循环之前测试 IndexError 值，并在该特定位置为列表分配一个零。比没有异常处理的插入。类似于：

for url in links:
    driver.get(url) #goes to the array and opens each link

    company = driver.find_elements_by_xpath("""//*[contains(@id, 'node')]/div[2]/ul/li/div/div[1]/span""") 
    date = driver.find_elements_by_xpath("""//*[contains(@id, 'node')]/div[1]/div[1]/div[2]/div/span""")
    ref = driver.find_elements_by_xpath("""//*[contains(@id, 'node')]/div[1]/div[3]""")
    title = driver.find_elements_by_xpath("""//*[@id="page-title"]/span""")
    urlinf = driver.current_url

    num_page_items = len(date)
    blank = "blank"

    companyStrings = []
    dateStrings = []
    refStrings = []
    titleStrings = []

    with open('results.csv', 'a') as f:
            for i in range(num_page_items):
                companyStrings.append( company[i].text )
                dateStrings.append( date[i].text )
                refStrings.append( ref[i].text )
                titleStrings.append( title[i].text ) 
                if companyStrings[i] == '':
                    companyStrings[i] = '0'
                if dateStrings[i] = '':
                    dateStrings[i] = '0'
                if refStrings[i] == '':
                    refStrings[i] = '0'
                if titleStrings[i] == '':
                    titleStrings[i] = '0'
                f.write(companyStrings[i] + "#" + dateStrings[i] + "#" + refStrings[i] + "#" + titleStrings[i] + "#" + urlinf + "\n")

driver.close()

当 Python 正在写入 CSV 时，脚本会在 csv 文件的 try / except 块中插入新行

While Python is writing to CSV, the script is inserting new line in try / except block in the csv file

python

selenium

web-scraping

index-error