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.

Tip

To parse XML code, use the readstruct function.

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="skip_link sr-only" href="#content_container">Skip to content</A>
    <A href="https://www.mathworks.com?s_tid=gn_logo" class="svg_link navbar-brand"><IMG src="/images/responsive/global/pic-header-mathworks-logo.svg" class="mw_logo" alt="MathWorks"/></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/products/get-matlab.html?s_tid=gn_getml">Get MATLAB</A>
    <A href="https://www.mathworks.com?s_tid=gn_logo" class="svg_link pull-left"><IMG src="/images/responsive/global/pic-header-mathworks-logo.svg" class="mw_logo" alt="MathWorks"/></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
    "Skip to content"
    ""
    "Products"
    "Solutions"
    "Academia"
    "Support"
    "Community"
    "Events"
    "Get MATLAB"
    ""

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"

Convert Parsed HTML Code to String

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 the htmlTree function.

tree = htmlTree(code);

Find all the paragraphs in the HTML tree using the findElement function. The paragraphs are the nodes with element name "P".

subtrees = findElement(tree,"P");

Convert the subtrees to string using the string function.

str = string(subtrees)

str = 26×1 string
    "<P class="h1">↵  <A href="../index.html" class="coming_from_product">Documentation</A>↵  <A href="../index.html" class="not_coming_from_product">Help Center</A>↵</P>"
    "<P>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.</P>"
    "<P>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.</P>"
    "<P>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.</P>"
    "<P class="category_desc">Learn the basics of Text Analytics Toolbox</P>"
    "<P class="category_desc">Import text data into MATLAB<SUP>®</SUP> and preprocess it for analysis</P>"
    "<P class="category_desc">Develop predictive models using topic models and word embeddings</P>"
    "<P class="category_desc">Visualize text data and models using word clouds and text scatter plots</P>"
    "<P class="category_desc">Information on language support in Text Analytics Toolbox</P>"
    "<P>You clicked a link that corresponds to this MATLAB command:</P>"
    "<P>Run the command by entering it in the MATLAB Command Window. Web browsers do not support MATLAB commands.</P>"
    "<P>Choose a web site to get translated content where available and see local events and offers. Based on your location, we recommend that you select: <STRONG class="recommended-country"/>.</P>"
    "<P>You can also select a web site from the following list:</P>"
    "<P>Select the China site (in Chinese or English) for best site performance. Other MathWorks country sites are not optimized for visits from your location.</P>"
    "<P class="text-center">↵  <A href="#" class="worldwide_link">Contact your local office</A>↵</P>"
    "<P class="ff_section_title">Explore Products</P>"
    "<P class="ff_section_title">Try or Buy</P>"
    "<P class="ff_section_title">Learn to Use</P>"
    "<P class="ff_section_title">Get Support</P>"
    "<P class="ff_section_title">About <SPAN translate="no">MathWorks</SPAN></P>"
    "<P class="h4 add_font_futura_medium add_margin_0">↵  <SPAN translate="no">MathWorks</SPAN>↵</P>"
    "<P>↵  <EM>Accelerating the pace of engineering and science</EM>↵</P>"
    "<P><SPAN translate="no">MathWorks</SPAN> is the leading developer of mathematical computing software for engineers and scientists.</P>"
    "<P>↵  <A href="/discovery.html?s_tid=all_disc_mw_ff">Discover...</A>↵</P>"
    "<P class="copyright" translate="no">© 1994-2021 The MathWorks, Inc.</P>"
    "<P>↵  <EM>Join the conversation</EM>↵</P>"

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

Compatibility Considerations

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`htmlTree` uses different algorithm for restructuring malformed HTML

Behavior changed in R2021a

When creating an htmlTree object, the software automatically restructures malformed input HTML code to have valid structure. This restructuring process includes adding, removing, and editing elements as well as rearranging the tree structure. Starting in R2021a, the software uses an updated algorithm to restructure malformed HTML. This change can result in htmlTree objects created in R2021a or later having different size, structure, and content when compared to previous releases.

Starting in R2021a, when loading htmlTree objects from MAT files created in an R2020b or before, the software automatically restructures the htmlTree object using the same algorithm used for creating htmlTree objects. When loading htmlTree objects from MAT files created in R2021a or later, the software does not restructure the htmlTree object.

This table highlights some notable steps of the restructuring process:

Step Change in Behavior

Automatically add head and title elements.

Step	Change in Behavior
Automatically add head and title elements.	Starting in R2021a, when creating an `htmlTree` object from HTML code, the software automatically inserts missing `<HEAD>`, `<TITLE>`, and other elements. In previous versions, the `htmlTree` object only included these elements when they are present in the input code. When loading `htmlTree` objects from MAT files created in an earlier release, the software automatically inserts `<HEAD>` and `<TITLE>` elements. When loading `htmlTree` objects from MAT files created in R2021a or later, the software does not automatically insert these elements.
Automatically add missing elements.	Starting in R2021a, when creating an `htmlTree` object from HTML code, the software automatically inserts missing elements when parent and child elements are inconsistent. For example, when a `<li>` (list item) element does not have a parent `<ul>` (unordered list) or `<ol>` (unordered list) element, the software automatically adds a `<ul>` element to make the HTML valid. This can result in different outputs when compared with earlier releases. When loading `htmlTree` objects from MAT files created in an earlier release, the software automatically inserts missing elements. When loading `htmlTree` objects from MAT files created in R2021a or later, the software does not automatically insert missing elements.
Discard parts of malformed code.	When creating an `htmlTree` object with malformed HTML code, the software may discard parts of the text. For example, if the input code is the string `"<div>a</"`, then the software discards the text `"a</"`.

Starting in R2021a, when creating an htmlTree object from HTML code, the software automatically inserts missing <HEAD>, <TITLE>, and other elements. In previous versions, the htmlTree object only included these elements when they are present in the input code.

When loading htmlTree objects from MAT files created in an earlier release, the software automatically inserts <HEAD> and <TITLE> elements. When loading htmlTree objects from MAT files created in R2021a or later, the software does not automatically insert these elements.

Automatically add missing elements.

Starting in R2021a, when creating an htmlTree object from HTML code, the software automatically inserts missing elements when parent and child elements are inconsistent. For example, when a <li> (list item) element does not have a parent <ul> (unordered list) or <ol> (unordered list) element, the software automatically adds a <ul> element to make the HTML valid. This can result in different outputs when compared with earlier releases.

When loading htmlTree objects from MAT files created in an earlier release, the software automatically inserts missing elements. When loading htmlTree objects from MAT files created in R2021a or later, the software does not automatically insert missing elements.

Discard parts of malformed code.

When creating an htmlTree object with malformed HTML code, the software may discard parts of the text. For example, if the input code is the string "<div>a</", then the software discards the text "a</".

htmlTree

Description

Creation

Syntax

Description

Input Arguments

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

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

Convert Parsed HTML Code to String

More About

HTML Elements

Compatibility Considerations

`htmlTree` uses different algorithm for restructuring malformed HTML

See Also

Topics

Text Analytics Toolbox Documentation

Support

Getting Started with Text Analytics in MATLAB

htmlTree

Description

Creation

Syntax

Description

Input Arguments

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

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

Convert Parsed HTML Code to String

More About

HTML Elements

Compatibility Considerations

htmlTree uses different algorithm for restructuring malformed HTML

See Also

Topics

Text Analytics Toolbox Documentation

Support

Getting Started with Text Analytics in MATLAB

`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

`htmlTree` uses different algorithm for restructuring malformed HTML