Xpath用法總結
阿新 • • 發佈：2018-12-23
<root xmlns:foo="http://www.foo.org/" xmlns:bar="http://www.bar.org"> <employees> <employee id="1">Johnny Dapp</employee> <employee id="2">Al Pacino</employee> <employee id="3">Robert De Niro</employee> </employees> <foo:companies> <foo:company id="4">Microsoft</foo:company> <foo:company id="5">IBM</foo:company> <foo:company id="6">Apple</foo:company> <foo:company id="7">Oracle</foo:company> </foo:companies> </root>
1、選擇文件節點
/
Document='<root xmlns:bar="http://www.bar.org" xmlns:foo="http://www.foo.org/"> <employees> <employee id="1">Johnny Dapp</employee> <employee id="2">Al Pacino</employee> <employee id="3">Robert De Niro</employee> </employees> <foo:companies> <foo:company id="4">Microsoft</foo:company> <foo:company id="5">IBM</foo:company> <foo:company id="6">Apple</foo:company> <foo:company id="7">Oracle</foo:company> </foo:companies> </root> '
2、選擇根元素
/root
Element='<root xmlns:bar="http://www.bar.org" xmlns:foo="http://www.foo.org/"> <employees> <employee id="1">Johnny Dapp</employee> <employee id="2">Al Pacino</employee> <employee id="3">Robert De Niro</employee> </employees> <foo:companies> <foo:company id="4">Microsoft</foo:company> <foo:company id="5">IBM</foo:company> <foo:company id="6">Apple</foo:company> <foo:company id="7">Oracle</foo:company> </foo:companies> </root>'
3、選擇所有employees下的employee
/root/employees/employee
Element='<employee id="1">Johnny Dapp</employee>'
Element='<employee id="2">Al Pacino</employee>'
Element='<employee id="3">Robert De Niro</employee>'
4、選擇所有foo:companies
//foo:companies
Element='<foo:companies xmlns:foo="http://www.foo.org/">
<foo:company id="4">Microsoft</foo:company>
<foo:company id="5">IBM</foo:company>
<foo:company id="6">Apple</foo:company>
<foo:company id="7">Oracle</foo:company>
</foo:companies>'
5、選擇所有foo:company屬性元素ID
//foo:companies/@id
Attribute='id=4'
Attribute='id=5'
Attribute='id=6'
Attribute='id=7'
6、選擇第二個employee的text
//employee[2]/text()
Text='Al Pacino'
7、選擇最後一個employee
//employee[last()]
Element='<employee id="3">Robert De Niro</employee>'
8、選擇第一個和第二個employee的text
//employee[position() <= 2]
Element='<employee id="1">Johnny Dapp</employee>'
Element='<employee id="2">Al Pacino</employee>'
9、選擇所有包含屬性ID的employee
//employee[@id]
Element='<employee id="1">Johnny Dapp</employee>'
Element='<employee id="2">Al Pacino</employee>'
Element='<employee id="3">Robert De Niro</employee>'
10、選擇屬性ID=3的employee
//employee[@id=3]
Element='<employee id="3">Robert De Niro</employee>'
11、選擇屬性ID<=3的employee
//employee[@id<=3]
Element='<employee id="1">Johnny Dapp</employee>'
Element='<employee id="2">Al Pacino</employee>'
Element='<employee id="3">Robert De Niro</employee>'
12、選擇companies下的所有元素
//foo:companies/*
Element='<foo:company xmlns:foo="http://www.foo.org/" id="4">Microsoft</foo:company>'
Element='<foo:company xmlns:foo="http://www.foo.org/" id="5">IBM</foo:company>'
Element='<foo:company xmlns:foo="http://www.foo.org/" id="6">Apple</foo:company>'
Element='<foo:company xmlns:foo="http://www.foo.org/" id="7">Oracle</foo:company>'
13、選擇文件中所有元素
//*
Element='<root xmlns:bar="http://www.bar.org" xmlns:foo="http://www.foo.org/">
<employees>
<employee id="1">Johnny Dapp</employee>
<employee id="2">Al Pacino</employee>
<employee id="3">Robert De Niro</employee>
</employees>
<foo:companies>
<foo:company id="4">Microsoft</foo:company>
<foo:company id="5">IBM</foo:company>
<foo:company id="6">Apple</foo:company>
<foo:company id="7">Oracle</foo:company>
</foo:companies>
</root>'
Element='<employees>
<employee id="1">Johnny Dapp</employee>
<employee id="2">Al Pacino</employee>
<employee id="3">Robert De Niro</employee>
</employees>'
Element='<employee id="1">Johnny Dapp</employee>'
14、選擇所有employee和foo:company
//employee|//foo:company
Element='<employee id="1">Johnny Dapp</employee>'
Element='<employee id="2">Al Pacino</employee>'
Element='<employee id="3">Robert De Niro</employee>'
Element='<foo:company xmlns:foo="http://www.foo.org/" id="4">Microsoft</foo:company>'
Element='<foo:company xmlns:foo="http://www.foo.org/" id="5">IBM</foo:company>'
Element='<foo:company xmlns:foo="http://www.foo.org/" id="6">Apple</foo:company>'
Element='<foo:company xmlns:foo="http://www.foo.org/" id="7">Oracle</foo:company>'
15、選擇第一個employee的id的值（數值表示）
number(//employee[1]/@id)
Double='1'
16、選擇第一個employee的id的值（字串表示）
string(//employee[1]/@id)
String='1'
17、第一個employee的文字長度
string-length(//employee[1]/text())
Int64='11'
18、Select the local name of the first ‘company’ element, i.e. without the namespace
local-name(//foo:company[1])
String='company'
19、計算foo:company的數量
count(//foo:company)
Int64='4'
20、計算所有company內ID屬性值的總和
sum(//foo:company/@id)
Double='22'
其他用法：
開啟百度，按下F12開啟開發者工具，左側標籤選擇Elements
按Ctrl+F進入搜尋，就可以練習Xpath啦！
21、contains
//*[contains(@name,"wd")]
定位了百度的輸入框
21、start-with 和 endwith（個人用的時候不行？不知道為什麼）
//*[start-with(@name,"wd")] #這個只是舉例，實際是找不到的