Leverage the uniqueness of IDs
As you know, IDs should be unique across a web page. If you can make sure this is the case, it can reduce the complexity of your scraping selectors drastically.
Here's the structure of an HTML page you might encounter in the wild:
<html>
<body>
<div id = 'first'>
<h1 class = 'big'>Joe Biden</h1>
<p class = 'first blue'>Democrat</p>
<p class = 'second blue'>Male</p>
</div>
<div id = 'second'>...</div>
<div id = 'third'>
<h1 class = 'big'>Donald Trump</h1>
<p class = 'first red'>Republican</p>
<p class = 'second red'>Male</p>
</div>
</body>
</html>
It has been read in for you with read_html() and is available through structured_html.
Это упражнение является частью курса
Web Scraping in R
Инструкции к упражнению
- Using
html_elements(), find the shortest possible selector to select the firstdivinstructured_html.
Интерактивное практическое упражнение
Попробуйте выполнить это упражнение, дополнив этот пример кода.
# Select the first div
structured_html %>%
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