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cheatsheets/xpath.md

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title layout
Xpath default

Descendant selectors

CSS Xpath ?
ul > li //ul/li ?
ul > li > a //ul/li/a
div > * //div/*
--- ---
h1 //h1 ?
div p //div//p ?
--- ---
h1 + ul //h1/following-sibling::ul ?
h1 + #id //h1/following-sibling::[@id="id"]
--- ---
:root / ?
:root > body /body
{:.greycode.no-head}

Attribute selectors

| CSS | Xpath | ? | | --- | --- | | | #id | //[@id="id"] | ? | | .class | //[@class="class"] ...see below | | | input[type="submit"] | //input[@type="submit"] | | | --- | --- | | | a[href^='/'] | //a[starts-with(@href, '/')] | ? | | a[href$='pdf'] | //a[ends-with(@href, '.pdf')] | | {:.greycode.no-head}

Order selectors

CSS Xpath ?
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()]
{:.greycode.no-head}

jQuery

jQuery Xpath ?
$('ul > li').parent() //ul/li/.. ?
$('li').closest('section') //li/ancestor-or-self::section
---- ----
$('a').attr('href') //a/@href ?
$('span').text() //span/text()
{:.greycode.no-head}

Other things

jQuery Xpath ?
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]
{:.greycode.no-head}

Class check

Xpath doesn't have the "check if part of space-separated list" operator, so this is the workaround:

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

Expressions

Prefixes

Begin your expression with any of these.

Prefix Example
// anywhere //hr[@class='edge']
./ relative ./a
/ root /html/body/div
{:.greycode.no-head}

Axes

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

Axis Example
/ child //ul/li/a
// descendant //[@id="list"]//a
{:.greycode.no-head}

Steps

A step may have an element name (div) and predicates ([...]). Both are optional.

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

They can also be these other things.

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

Predicates

Predicates ([...])

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

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

Operators

Use comparison and logic operators to make conditionals.

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

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

Using nodes

You can use nodes inside predicates.

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

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

Indexing

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

//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)

Chaining order

Order is significant, these two are different.

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

Nesting predicates

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

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

Functions

Node functions

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

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

Boolean functions

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

String functions

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

string()
number()
boolean()

Axes

Using axes

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/li                       # $('ul > li')
//ul/ancestor-or-self::li     # $('ul').closest('li')

{:.light}

Descendant-or-self axis

When you use // for descendants, this is short for the descendant-or-self:: axis.

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

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

Child axis

When axis is not specified, a name is short for child::name. This is what makes //a/b/c work.

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

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

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

Attribute axis

When you use @ for attributes, that's short for the attribute:: axis.

# both the same
  //a/@href
  //a/attribute::href

# both the same
  //div[@id="box"]
  //div[attribute::id="box"]

Other axes

There are other axes you can use.

Axis Abbrev Description
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
{:.greycode}

More 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 <section> that directly contains h1#section-name
  //section[h1[@id='section-name']]

# Find a <section> that contains h1#section-name
# (Same as above, but use descendant-or-self instead of child)
  //section[//*[@id='section-name']]

# like jQuery's $().closest('.box')
  ./ancestor-or-self::[@class="box"]

# Find <item> and check its attributes
  //item[@price > 2*@discount]

References