The selectors supported by lxml include XPath selector, CSS selector, find method, findall method, iter method, get method and text attribute, etc. Detailed introduction: 1. XPath selector. XPath is a language used to locate elements in XML and HTML documents. lxml selects elements by using XPath expressions. The XPath selector is very powerful and can be based on the tag name and attributes of the element. , hierarchical relationship and other conditions to select; 2. CSS selector and so on.
The operating system for this tutorial: Windows 10 system, DELL G3 computer.
lxml is a Python library for processing XML and HTML documents. It provides rich functionality and flexible selectors for locating and extracting required elements in the document. lxml supports the following selectors:
1. XPath selector: XPath is a language used to locate elements in XML and HTML documents. lxml selects elements by using XPath expressions. The XPath selector is very powerful and can select based on multiple conditions such as the element's tag name, attributes, hierarchical relationships, etc. For example, `//div[@class="red"]` means to select all div elements with the class attribute "red".
2. CSS selector: lxml also supports selector syntax similar to CSS. By using CSS selectors, you can select and extract elements more conveniently. For example, `div.red` means to select all div elements with the class attribute "red". lxml's CSS selector function is based on the CSS3 selector specification.
3. Find method: lxml provides the find method, which is used to find and return the first matching element based on specified conditions. The find method can accept XPath expressions or CSS selectors as parameters. For example, `element.find(".red")` means to find the first element with a class attribute of "red" among the child elements of the element element.
4. findall method: Similar to the find method, lxml also provides the findall method, which is used to find all matching elements and return a list of elements. The findall method can also accept XPath expressions or CSS selectors as parameters. For example, `element.findall(".//div")` means to find all div elements in the descendant elements of the element element.
5. iter method: lxml's iter method is used to iterate through the elements in the document. You can use XPath expressions or CSS selectors as parameters to filter the required elements. For example, `element.iter("div")` means iterating through all div elements under the element element.
6. get method: The element object of lxml provides the get method, which is used to obtain the value of the specified attribute. You can get the attribute value of an element by specifying the attribute name. For example, `element.get("class")` means to get the class attribute value of element element.
7. text attribute: The lxml element object also provides the text attribute, which is used to obtain the text content of the element. For example, `element.text` means getting the text content of the element element.
By using lxml's selectors, we can flexibly locate and extract elements in XML and HTML documents. Whether using XPath or CSS selectors, lxml provides a concise and powerful syntax to meet different needs. At the same time, lxml also provides many other functions, such as modifying element content, adding new elements, deleting elements, etc., which can help us process and operate documents more comprehensively.
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