python + positioning of the element selenium XPath learning 01

Reference Document 1: https: //www.w3school.com.cn/xpath/xpath_syntax.asp

 

Reference Document 2: https://www.runoob.com/xpath/xpath-tutorial.html

 

XML instance document

We will use this XML document in the following example:

<?xml version="1.0" encoding="ISO-8859-1"?>

<bookstore>

<book>
  <title lang="eng">Harry Potter</title>
  <price>29.99</price>
</book>

<book>
  <title lang="eng">Learning XML</title>
  <price>39.95</price>
</book>

</bookstore>

Select node

XPath uses path expressions to select nodes in an XML document. Along the path through the node, or to select a step.

Listed below are the most useful path expressions:

expression	description
nodename	Select all the child nodes of this node.
/	From the root node selected.
//	From match to select the document node selection of the current node, regardless of their location .
.	Select the current node.
..	Select the parent of the current node.
@	Select Properties .

Examples

In the table below, we have listed the results of some path expressions and expressions:

Path expression	result
bookstore	Selects all child nodes of the bookstore element.
/bookstore	Select the root element bookstore. Note: If the path starts with a forward slash (/), then this path is always representative of the absolute path to an element!
bookstore/book	Select the sub-elements belonging to the bookstore of the book all the elements.
//book	Select all book sub-elements, regardless of their position in the document.
bookstore//book	Select all book elements that belong to the descendants of the bookstore element, and no matter what position they are located below the bookstore.
// @ lang	Select all of the property named lang.

 

 

Predicate (Predicates)

Predicate is used to search for a particular node or contains a value specified node.

Predicate is embedded in square brackets in.

Examples

In the table below, we have listed some path expressions with predicates, and the result of the expression:

Path expression	result
/bookstore/book[1]	Select an element belonging to the first sub bookstore book element.
/bookstore/book[last()]	Select the sub-elements belonging to the bookstore last book element.
/bookstore/book[last()-1]	Select the sub-elements belonging to the reciprocal bookstore's second book element.
/bookstore/book[position()<3]	Select book element belonging to two sub-elements of the bookstore element foremost.
//title[@lang]	Select all of lang has a property named title element.
// title [@ lang = 'What']	Select all the title elements, and these elements have a lang attribute value of eng.
/bookstore/book[price>35.00]	Select all the book elements bookstore element, and wherein the price element value must be greater than 35.00.
/bookstore/book[price>35.00]/title	Select all the title elements of the book element bookstore element, and wherein the value of the price element must be greater than 35.00.

Select the unknown node

XPath wildcards can be used to select unknown XML elements.

Tsuhaifu	description
*	Matches any element node.
@*	Matches any attribute node.
node()	Match any type of node.

Examples

In the table below, we have listed some path expressions and the result of these expressions:

Path expression	result
/bookstore/*	Select the bookstore element of all child elements.
//*	Select all elements in the document.
//title[@*]	Select all the title elements with attributes.

 

 

Select several paths

By using the path expression "|" operator, you can select several paths.

Examples

In the table below, we have listed some path expressions and the result of these expressions:

Path expression	result
//book/title | //book/price	Select the book title and price elements of all the elements.
//title | //price	Select all title and price elements in the document.
/bookstore/book/title | //price	Select book element of the bookstore element belonging to all the title elements, as well as document all the price elements.