htmlTree

Parsed HTML tree

Description

An htmlTree object represents a parsed HTML element or node. Extract parts of interest using the findElement function or the Children property, and extract text using the extractHTMLText function.

Creation

Syntax

tree = htmlTree(code)

Description

example

tree = htmlTree(code) parses the HTML code in the string code and returns the resulting tree structure.

Input Arguments

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`code` — HTML code
string array | character vector | cell array of character vectors

HTML code, specified as a string array, a character vector, or a cell array of character vectors.

Tip

To read HTML code from a web page, use webread.
To extract text from an HTML file, use extractFileText.

Example: "<a href='https://www.mathworks.com'>MathWorks</a>"

Data Types: char | string | cell

Properties

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`Children` — Direct descendants of element
`htmlTree` array

Direct descendants of the element, specified as an htmlTree array.

`Parent` — Parent node
`htmlTree` object

Parent node in the tree, specified as an htmlTree object.

If the HTML tree is a root node, then the value of Parent is missing.

`Name` — HTML element name
string scalar

HTML element name, specified as a string scalar.

For more information, see HTML Elements.

Object Functions

`findElement`	Find elements in HTML tree
`getAttribute`	Read HTML attribute of root node of HTML tree
`extractHTMLText`	Extract text from HTML
`ismissing`	Find HTML trees without values

Examples

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Parse HTML Code

Open Live Script

Read HTML code from the URL https://www.mathworks.com/help/textanalytics using webread.

url = "https://www.mathworks.com/help/textanalytics";
code = webread(url);

Parse the HTML code using htmlTree.

tree = htmlTree(code);

View the element name of the root node of the tree.

tree.Name

ans = 
"HTML"

View the children of the root node.

tree.Children

ans = 
  4×1 htmlTree:

    " "
    <HEAD><TITLE>Text Analytics Toolbox Documentation</TITLE><META charset="utf-8"/><META content="width=device-width, initial-scale=1.0" name="viewport"/><META content="IE=edge" http-equiv="X-UA-Compatible"/><LINK href="/includes_content/responsive/css/bootstrap/bootstrap.min.css" rel="stylesheet" type="text/css"/><LINK href="/includes_content/responsive/css/site6.css?201903" rel="stylesheet" type="text/css"/><LINK href="/includes_content/responsive/css/site6_lg.css?201903" media="screen and (min-width: 1200px)" rel="stylesheet"/><LINK href="/includes_content/responsive/css/site6_md.css?201903" media="screen and (min-width: 992px) and (max-width: 1199px)" rel="stylesheet"/><LINK href="/includes_content/responsive/css/site6_sm+xs.css?201903" media="screen and (max-width: 991px)" rel="stylesheet"/><LINK href="/includes_content/responsive/css/site6_sm.css?201903" media="screen and (min-width: 768px) and (max-width: 991px)" rel="stylesheet"/><LINK href="/includes_content/responsive/css/site6_…
    " "
    <BODY id="responsive_offcanvas"><!-- Mobile TopNav: Start --><DIV class="header visible-xs visible-sm" id="header_mobile" translate="no"><NAV class="navbar navbar-default" role="navigation"><DIV class="container-fluid"><DIV class="row"><DIV class="col-xs-12"><DIV class="navbar-header"><BUTTON class="navbar-toggle topnav_toggle" data-target="#topnav_collapse" data-toggle="collapse" type="button"><SPAN class="sr-only">Toggle Main Navigation</SPAN><SPAN class="icon-menu"/></BUTTON><A class="svg_link navbar-brand" href="https://www.mathworks.com?s_tid=gn_logo"><IMG alt="MathWorks" class="mw_logo" src="/images/responsive/global/pic-header-mathworks-logo.svg"/></A></DIV></DIV></DIV><DIV class="row visible-xs visible-sm"><DIV class="col-xs-12"><DIV class="navbar-collapse collapse" id="topnav_collapse"><UL class="nav navbar-nav" id="topnav"><LI class="headernav_login"><A class="mwa-nav_login" href="https://www.mathworks.com/login?uri=http://www.mathworks.com/help/textanalytics/index.html">Sign…

Extract the text from the HTML tree using extractHTMLText.

str = extractHTMLText(tree)

str = 
    "Text Analytics Toolbox™ provides algorithms and visualizations for preprocessing, analyzing, and modeling text data. Models created with the toolbox can be used in applications such as sentiment analysis, predictive maintenance, and topic modeling.
     
     Text Analytics Toolbox includes tools for processing raw text from sources such as equipment logs, news feeds, surveys, operator reports, and social media. You can extract text from popular file formats, preprocess raw text, extract individual words, convert text into numerical representations, and build statistical models.
     
     Using machine learning techniques such as LSA, LDA, and word embeddings, you can find clusters and create features from high-dimensional text datasets. Features created with Text Analytics Toolbox can be combined with features from other data sources to build machine learning models that take advantage of textual, numeric, and other types of data."

Find Elements in HTML Tree

Open Live Script

Read HTML code from the URL https://www.mathworks.com/help/textanalytics using the webread function.

url = "https://www.mathworks.com/help/textanalytics";
code = webread(url);

Parse the HTML code using htmlTree.

tree = htmlTree(code);

Find all the hyperlinks in the HTML tree using findElement. The hyperlinks are nodes with element name "A".

selector = "A";
subtrees = findElement(tree,selector);

View the first few subtrees.

subtrees(1:10)

ans = 
  10×1 htmlTree:

    <A class="svg_link navbar-brand" href="https://www.mathworks.com?s_tid=gn_logo"><IMG alt="MathWorks" class="mw_logo" src="/images/responsive/global/pic-header-mathworks-logo.svg"/></A>
    <A class="mwa-nav_login" href="https://www.mathworks.com/login?uri=http://www.mathworks.com/help/textanalytics/index.html">Sign In</A>
    <A href="https://www.mathworks.com/products.html?s_tid=gn_ps">Products</A>
    <A href="https://www.mathworks.com/solutions.html?s_tid=gn_sol">Solutions</A>
    <A href="https://www.mathworks.com/academia.html?s_tid=gn_acad">Academia</A>
    <A href="https://www.mathworks.com/support.html?s_tid=gn_supp">Support</A>
    <A href="https://www.mathworks.com/matlabcentral/?s_tid=gn_mlc">Community</A>
    <A href="https://www.mathworks.com/company/events.html?s_tid=gn_ev">Events</A>
    <A href="https://www.mathworks.com/company/aboutus/contact_us.html?s_tid=gn_cntus">Contact Us</A>
    <A href="https://www.mathworks.com/store?s_cid=store_top_nav&amp;s_tid=gn_store">How to Buy</A>

Extract the text from the subtrees using extractHTMLText. The result contains the link text from each link on the page.

str = extractHTMLText(subtrees);
str(1:10)

ans = 10×1 string array
    ""
    "Sign In"
    "Products"
    "Solutions"
    "Academia"
    "Support"
    "Community"
    "Events"
    "Contact Us"
    "How to Buy"

Get Attribute of HTML Tag

Open Live Script

Read HTML code from the URL https://www.mathworks.com/help/textanalytics using webread.

url = "https://www.mathworks.com/help/textanalytics";
code = webread(url);

Parse the HTML code using htmlTree.

tree = htmlTree(code);

Find all the hyperlinks in the HTML tree using findElement. The hyperlinks are the nodes with element name "A".

selector = "A";
subtrees = findElement(tree,selector);
subtrees(1:10)

ans = 
  10×1 htmlTree:

    <A class="svg_link navbar-brand" href="https://www.mathworks.com?s_tid=gn_logo"><IMG alt="MathWorks" class="mw_logo" src="/images/responsive/global/pic-header-mathworks-logo.svg"/></A>
    <A class="mwa-nav_login" href="https://www.mathworks.com/login?uri=http://www.mathworks.com/help/textanalytics/index.html">Sign In</A>
    <A href="https://www.mathworks.com/products.html?s_tid=gn_ps">Products</A>
    <A href="https://www.mathworks.com/solutions.html?s_tid=gn_sol">Solutions</A>
    <A href="https://www.mathworks.com/academia.html?s_tid=gn_acad">Academia</A>
    <A href="https://www.mathworks.com/support.html?s_tid=gn_supp">Support</A>
    <A href="https://www.mathworks.com/matlabcentral/?s_tid=gn_mlc">Community</A>
    <A href="https://www.mathworks.com/company/events.html?s_tid=gn_ev">Events</A>
    <A href="https://www.mathworks.com/company/aboutus/contact_us.html?s_tid=gn_cntus">Contact Us</A>
    <A href="https://www.mathworks.com/store?s_cid=store_top_nav&amp;s_tid=gn_store">How to Buy</A>

Get the hyperlink references using getAttribute. Specify the attribute name "href".

attr = "href";
str = getAttribute(subtrees,attr);
str(1:10)

ans = 10×1 string array
    "https://www.mathworks.com?s_tid=gn_logo"
    "https://www.mathworks.com/login?uri=http://www.mathworks.com/help/textanalytics/index.html"
    "https://www.mathworks.com/products.html?s_tid=gn_ps"
    "https://www.mathworks.com/solutions.html?s_tid=gn_sol"
    "https://www.mathworks.com/academia.html?s_tid=gn_acad"
    "https://www.mathworks.com/support.html?s_tid=gn_supp"
    "https://www.mathworks.com/matlabcentral/?s_tid=gn_mlc"
    "https://www.mathworks.com/company/events.html?s_tid=gn_ev"
    "https://www.mathworks.com/company/aboutus/contact_us.html?s_tid=gn_cntus"
    "https://www.mathworks.com/store?s_cid=store_top_nav&s_tid=gn_store"

More About

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HTML Elements

A typical HTML element contains the following components:

Element name – Name of the HTML tag. The element name corresponds to the Name property of the HTML tree.
Attributes – Additional information about the tag. HTML attributes have the form name="value", where name and value denote the attribute name and value respectively. The attributes appear inside the opening HTML tag. To get the attribute values from an HTML tree, use getAttribute.
Content – Element content. The content appears between opening and closing HTML tags. The content can be text data or nested HTML elements. To extract the text from an htmlTree object, use extractHTMLText. To get the nested HTML elements of an htmlTree object, use the Children property.

For example, the HTML element <a href="https://www.mathworks.com">Home</a> comprises the following components:

Component		Value	Description
Element name		`a`	Element is a hyperlink
Attribute	Attribute name	`href`	Hyperlink reference
Attribute	Attribute value	`"https://www.mathworks.com"`	Hyperlink reference value
Content		`Home`	Text to display

htmlTree

Description

Creation

Syntax

Description

Input Arguments

`code` — HTML code
string array | character vector | cell array of character vectors

Tip

Properties

`Children` — Direct descendants of element
`htmlTree` array

`Parent` — Parent node
`htmlTree` object

`Name` — HTML element name
string scalar

Object Functions

Examples

Parse HTML Code

Find Elements in HTML Tree

Get Attribute of HTML Tag

More About

HTML Elements

See Also

Topics

Introduced in R2018b

Text Analytics Toolbox Documentation

Support

Machine Learning with Text: Get Started with Text Analytics

htmlTree

Description

Creation

Syntax

Description

Input Arguments

code — HTML code string array | character vector | cell array of character vectors

Tip

Properties

Children — Direct descendants of element htmlTree array

Parent — Parent node htmlTree object

Name — HTML element name string scalar

Object Functions

Examples

Parse HTML Code

Find Elements in HTML Tree

Get Attribute of HTML Tag

More About

HTML Elements

See Also

Topics

Introduced in R2018b

Text Analytics Toolbox Documentation

Support

Machine Learning with Text: Get Started with Text Analytics

`code` — HTML code
string array | character vector | cell array of character vectors

`Children` — Direct descendants of element
`htmlTree` array

`Parent` — Parent node
`htmlTree` object

`Name` — HTML element name
string scalar