Querying data with XPath and CSS selectors

CSS selectors are patterns used for selectingelements and are often used to define the elements that styles should be applied to. They can also be used with lxml to select nodes in the DOM. CSS selectors are commonly used as they are more compact than XPath and generally can be more reusable in code. Examples of common selectors which may be used are as follows:

What you are looking for	Example
All tags	*
A specific tag (that is, tr)	.planet
A class name (that is, "planet")	tr.planet
A tag with an ID "planet3"	tr#planet3
A child tr of a table	table tr
A descendant tr of a table	table tr
A tag with an attribute (that is, tr with id="planet4")	a[id=Mars]

Getting ready

Let's start examining CSS selectors using the same start up code we used in the last recipe.  These code snippets are also in the 02/04_css_selectors.py.

In [1]: from lxml import html
   ...: import requests
   ...: page_html = requests.get("http://localhost:8080/planets.html").text
   ...: tree = html...