如何更正R中的Sprintf输入以更改XPath中的值？

问题描述

有一系列XPath，它们与网页上的职位列表相对应。

例如一个职位的XPath是//*[@id="ctl00_CPH1_vcyS_vsGrid_ctl00_ctl04_Title"] 另一个职位的XPath是//*[@id="ctl00_CPH1_vcyS_vsGrid_ctl00_ctl10_Title"]

其中更改的模式是XPath 04部分中的数字（例如ctl04）。

因此，我想编写一个for循环，该循环在XPath上进行迭代，从04到18以1的步长进行循环。我有以下代码：

for (i in seq(from = 04,to = 18,by = 1)) {
title_xpath <- sprintf('//*[@id="ctl00_CPH1_vcyS_vsGrid_ctl00_ctl%g_Title"]',i)
}

我假设通过sprintf，'%g'将被for循环中的i值替换（即尝试04，然后05，依此类推），最多18。但这不是不会发生。

有什么想法吗？

编辑：感谢到目前为止的建议。但是，当我运行完整的代码（如下所示）时，它们不起作用：

title_list <- list()
item_count <- 1

for (i in seq(from = 1,by = 1)) {
   
  title_xpath <- sprintf('//*[@id="ctl00_CPH1_vcyS_vsGrid_ctl00_ctl%02d_Title"]',i)
    
  
  # Find the element on the website and transform it to text directly
  job_title <- driver$findElement(using = "xpath",value = title_xpath)$getElementText()[[1]]
  
  # Add the outcome to the list
  title_list[[item_count]] <- job_title
  item_count <- item_count + 1
  
}

print(title_list)

其中不起作用的部分与XPath有关。如果将XPath从ctl%02d更改为ctl04，位置ctl04的职位将被打印18次。我想要的是代码打印与ctl04，ctl05等对应的职位，直到ctl18。帮助表示赞赏。

解决方法

可能您需要%02d：

title_xpath <- sprintf('//*[@id="ctl00_CPH1_vcyS_vsGrid_ctl00_ctl%02d_Title"]',4:18)
title_xpath

# [1] "//*[@id=\"ctl00_CPH1_vcyS_vsGrid_ctl00_ctl04_Title\"]"
# [2] "//*[@id=\"ctl00_CPH1_vcyS_vsGrid_ctl00_ctl05_Title\"]"
# [3] "//*[@id=\"ctl00_CPH1_vcyS_vsGrid_ctl00_ctl06_Title\"]"
# [4] "//*[@id=\"ctl00_CPH1_vcyS_vsGrid_ctl00_ctl07_Title\"]"
# [5] "//*[@id=\"ctl00_CPH1_vcyS_vsGrid_ctl00_ctl08_Title\"]"
# [6] "//*[@id=\"ctl00_CPH1_vcyS_vsGrid_ctl00_ctl09_Title\"]"
# [7] "//*[@id=\"ctl00_CPH1_vcyS_vsGrid_ctl00_ctl10_Title\"]"
# [8] "//*[@id=\"ctl00_CPH1_vcyS_vsGrid_ctl00_ctl11_Title\"]"
# [9] "//*[@id=\"ctl00_CPH1_vcyS_vsGrid_ctl00_ctl12_Title\"]"
#[10] "//*[@id=\"ctl00_CPH1_vcyS_vsGrid_ctl00_ctl13_Title\"]"
#[11] "//*[@id=\"ctl00_CPH1_vcyS_vsGrid_ctl00_ctl14_Title\"]"
#[12] "//*[@id=\"ctl00_CPH1_vcyS_vsGrid_ctl00_ctl15_Title\"]"
#[13] "//*[@id=\"ctl00_CPH1_vcyS_vsGrid_ctl00_ctl16_Title\"]"
#[14] "//*[@id=\"ctl00_CPH1_vcyS_vsGrid_ctl00_ctl17_Title\"]"
#[15] "//*[@id=\"ctl00_CPH1_vcyS_vsGrid_ctl00_ctl18_Title\"]"