R,使用XML和xpathSApply时的右xpath表达式

假设我使用下面的表达式解析了一个网站

library(XML)
url.df_1 = htmlTreeParse("http://www.appannie.com/app/android/com.king.candycrushsaga/",useInternalNodes = T)

如果我在代码下运行,

xpathSApply(url.df_1,"//div[@class='app_content_section']/h3",function(x) c(xmlValue(x),xmlAttrs(x)[["href"]]))

我会得到以下 –

[1] "Description"                      "What's new"                      
[3] "Permissions"                      "More Apps by King.com All Apps  »"
[5] "Customers Also Viewed"            "Customers Also Installed"

现在,我感兴趣的只是“客户也安装”部分.但是,当我运行以下代码时,"//div[@class='app_content_section']/ul/li/a",xmlAttrs(x)[["href"]]))

它将“King.com所有应用程序中的更多应用程序”,“还查看了客户”和“客户也已安装”中包含的所有应用程序吐出.

所以我试过,"//div[h3='Customers Also Installed']”,xmlAttrs(x)[["href"]]))

但这没用.所以我试过了

xpathSApply(url.df_1,"//div[contains(.,'Customers Also Installed')]",xmlValue)

但这也不起作用. (输出应该如下所示)

[,1]                                                
[1,] "Christmas Candy Free\n    Daniel Development\n    "
[2,] "/app/android/xmas.candy.free/"                     
 [,2]                                           
[1,] "Jewel Candy Maker\n    Nutty Apps\n    "      
[2,] "/app/android/com.candy.maker.jewel.nuttyapps/"
 [,3]                                      
[1,] "Pogz 2\n    Terry Paton\n    "           
[2,] "/app/android/com.terrypaton.unity.pogz2/"

任何指导将不胜感激！

解决方法

这是一个选项(你真的很接近)：

xpathSApply(url.df_1,'Customers Also Installed')]/*/li/a",xmlGetAttr,'href')

[1] "/app/android/xmas.candy.free/"                
[2] "/app/android/com.candy.maker.jewel.nuttyapps/"
[3] "/app/android/com.terrypaton.unity.pogz2/"