Xpath Cheatsheet

xpath

 2018/01/02

Xpath test bed(链接地址)

Test queries in the Xpath test bed:
Xpath test bed (whitebeam.org)

Browser console

1	$x('//div')

Works in Firefox and Chrome.

Selectors

Descendant selectors

`h1`	`//h1`	?
`div p`	`//div//p`	?
`ul > li`	`//ul/li`	?
`ul > li > a`	`//ul/li/a`
`div > *`	`//div/*`
`:root`	`/`	?
`:root > body`	`/body`

Attribute selectors

`#id`	`//[@id="id"]`	?
`.class`	`//[@class="class"]` …kinda
`input[type="submit"]`	`//input[@type="submit"]`
`a#abc[for="xyz"]`	`//a[@id="abc"][@for="xyz"]`	?
`a[rel]`	`//a[@rel]`
`a[href^='/']`	`//a[starts-with(@href, '/')]`	?
`a[href$='pdf']`	`//a[ends-with(@href, '.pdf')]`
`a[href~='://']`	`//a[contains(@href, '://')]` …kinda

Order selectors

`ul > li:first-child`	`//ul/li[1]`	?
`ul > li:nth-child(2)`	`//ul/li[2]`
`ul > li:last-child`	`//ul/li[last()]`
`li#id:first-child`	`//li[@id="id"][1]`
`a:first-child`	`//a[1]`
`a:last-child`	`//a[last()]`

Siblings

`h1 ~ ul`	`//h1/following-sibling::ul`	?
`h1 + ul`	`//h1/following-sibling::ul[1]`
`h1 ~ #id`	`//h1/following-sibling::[@id="id"]`

jQuery

`$('ul > li').parent()`	`//ul/li/..`	?
`$('li').closest('section')`	`//li/ancestor-or-self::section`
`$('a').attr('href')`	`//a/@href`	?
`$('span').text()`	`//span/text()`

Other things

`h1:not([id])`	`//h1[not(@id)]`	?
Text match	`//button[text()="Submit"]`	?
Text match (substring)	`//button[contains(text(),"Go")]`
Arithmetic	`//product[@price > 2.50]`
Has children	`//ul[*]`
Has children (specific)	`//ul[li]`
Or logic	`//a[@name or @href]`	?
Union (joins results)	`//a	//div`	?

Class check

1	//div[contains(concat(' ',normalize-space(@class),' '),' foobar ')]

Xpath doesn’t have the “check if part of space-separated list” operator, so this is the workaround (source).

Expressions

Steps and axes

`//`	`ul`	`/`	`a[@id='link']`
Axis	Step	Axis	Step

Prefixes

Prefix	Example	What
`//`	`//hr[@class='edge']`	Anywhere
`./`	`./a`	Relative
`/`	`/html/body/div`	Root

Begin your expression with any of these.

Axes

Axis	Example	What
`/`	`//ul/li/a`	Child
`//`	`//[@id="list"]//a`	Descendant

Separate your steps with /. Use two (//) if you don’t want to select direct children.

Steps

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//div
//div[@name='box']
//[@id='link']

A step may have an element name (div) and predicates ([...]). Both are optional. They can also be these other things:

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//a/text()     #=> "Go home"
//a/@href      #=> "index.html"
//a/*          #=> All a's child elements

Predicates

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//div[true()] 
//div[@class="head"]
//div[@class="head"][@id="top"]

Restricts a nodeset only if some condition is true. They can be chained.

Operators

# Comparison
//a[@id = "xyz"]
//a[@id != "xyz"]
//a[@price > 25]

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# Logic (and/or)
//div[@id="head" and position()=2]
//div[(x and y) or not(z)]

Use comparison and logic operators to make conditionals.

Using nodes

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# Use them inside functions
//ul[count(li) > 2]
//ul[count(li[@class='hide']) > 0]

1 2	# This returns `<ul>` that has a `<li>` child //ul[li]

You can use nodes inside predicates.

Indexing

//a[1]                  # first <a>
//a[last()]             # last <a>
//ol/li[2]              # second <li>
//ol/li[position()=2]   # same as above
//ol/li[position()>1]   # :not(:first-child)

Use [] with a number, or last() or position().

Chaining order

1 2	a[1][@href='/'] a[@href='/'][1]

Order is significant, these two are different.

Nesting predicates

1	//section[//h1[@id='hi']]

This returns <section> if it has an <h1> descendant with id='hi'.

Functions

Node functions

name()                     # //[starts-with(name(), 'h')]
text()                     # //button[text()="Submit"]
                           # //button/text()
lang(str)
namespace-uri()

1 2	count() # //table[count(tr)=1] position() # //ol/li[position()=2]

Boolean functions

1	not(expr) # button[not(starts-with(text(),"Submit"))]

String functions

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contains()                 # font[contains(@class,"head")]
starts-with()              # font[starts-with(@class,"head")]
ends-with()                # font[ends-with(@class,"head")]

concat(x,y)
substring(str, start, len)
substring-before("01/02", "/")  #=> 01
substring-after("01/02", "/")   #=> 02
translate()
normalize-space()
string-length()

Type conversion

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string()
number()
boolean()

Axes

Using axes

//ul/li                       # ul > li
//ul/child::li                # ul > li (same)
//ul/following-sibling::li    # ul ~ li
//ul/descendant-or-self::li   # ul li
//ul/ancestor-or-self::li     # $('ul').closest('li')

Steps of an expression are separated by /, usually used to pick child nodes. That’s not always true: you can specify a different “axis” with ::.

`//`	`ul`	`/child::`	`li`
Axis	Step	Axis	Step

Child axis

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# both the same
//ul/li/a
//child::ul/child::li/child::a

child:: is the default axis. This makes //a/b/c work.

# both the same
# this works because `child::li` is truthy, so the predicate succeeds
//ul[li]
//ul[child::li]

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# both the same
//ul[count(li) > 2]
//ul[count(child::li) > 2]

Descendant-or-self axis

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# both the same
//div//h4
//div/descendant-or-self::h4

// is short for the descendant-or-self:: axis.

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# both the same
//ul//[last()]
//ul/descendant-or-self::[last()]

Other axes

Axis	Abbrev	Notes
`ancestor`
`ancestor-or-self`
`attribute`	`@`	`@href` is short for `attribute::href`
`child`		`div` is short for `child::div`
`descendant`
`descendant-or-self`	`//`	`//` is short for `/descendant-or-self::node()/`
`namespace`
`self`	`.`	`.` is short for `self::node()`
`parent`	`..`	`..` is short for `parent::node()`
`following`
`following-sibling`
`preceding`
`preceding-sibling`

There are other axes you can use.

Unions

1	//a \| //span

Use | to join two expressions.

More examples

Examples

//*                 # all elements
count(//*)          # count all elements
(//h1)[1]/text()    # text of the first h1 heading
//li[span]          # find a <li> with an <span> inside it
                    # ...expands to //li[child::span]
//ul/li/..          # use .. to select a parent

Find a parent

1	//section[h1[@id='section-name']]

Finds a <section> that directly contains h1#section-name

1 2	# Find a <section> that contains h1#section-name //section[//*[@id='section-name']]

Finds a <section> that contains h1#section-name. (Same as above, but uses descendant-or-self instead of child)

Closest

1	./ancestor-or-self::[@class="box"]

Works like jQuery’s $().closest('.box').

Attributes

1	//item[@price > 2*@discount]

Finds <item> and check its attributes

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