Parsed HTML tree
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.
code — HTML codeHTML 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
Children — Direct descendants of elementhtmlTree arrayDirect descendants of the element, specified as an htmlTree
array.
Parent — Parent nodehtmlTree objectParent 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 nameHTML element name, specified as a string scalar.
For more information, see HTML Elements.
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 |
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."
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 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/products/get-matlab.html?s_tid=gn_getml">Get MATLAB</A>
<A class="svg_link pull-left" 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>
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
""
"Products"
"Solutions"
"Academia"
"Support"
"Community"
"Events"
"Contact Us"
"Get MATLAB"
""
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&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"
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"namevaluegetAttribute.
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 value | "https://www.mathworks.com" | Hyperlink reference value | |
| Content | Home | Text to display | |
extractHTMLText | findElement | getAttribute | ismissing | readPDFFormData | tokenizedDocument
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