CS计算机代考程序代写 Java concurrency data science database prolog javascript SQL Excel flex python COMP20008

XML: eXtensible Markup Language
• Extensible: user defined tags
• Facilitate better encoding of semantics
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Subject guide in plain-text
Year of offer = 2019
Subject level = Undergraduate level 2 Subject code = COMP20008
Campus = Parkville
Availability = Semester 1, Semester 2
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Subject guide in HTML – cont.
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Subject guide in xml
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XML syntax – well formed
• begin with declaration, the XML prolog.
• Elements
• One root element
• Properly nested
• Attribute values must be quoted • Must have a closing tag:
• Parkville
(self closing tag with an attribute) • Case sensitive
• comments

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XML syntax – cont.
• Preserves white spaces. I think … therefore I am • some characters have special meaning
• ‘<’ and ‘&’ are strictly illegal inside an element • all books & videos are now < AUD 10
• allbooks&videosarenow<AUD10
• CDATA (character data) section may be used inside XML element to include large blocks of text, which may contain these special characters such as &,
>
• •
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XML applications
• A ‘meta’ mark-up language.
• Mathematical Markup Language (MathML)
• ChemML (Chemical Markup Language)
• FHIR (Health/Medical data: http://hl7.org/fhir) • RSS, SOAP, SVG, …
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MathML example: markup an equation
In MathML, x3+6x+6 is represented as

x 3
+
6 &InvisibleTimes; x
+
6
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XML vs HTML
• Extensible — non-extensible
• Case sensitive — not case sensitive • Focus on semantics — display

Break

Semi-structured Data – JSON
JSON
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JavaScript Object Notation (JSON)
• JSON (www.json.org)
• Douglas Crockford (pretty much alone)
• c.f the development of XML by committee
• “Javascript: the good parts” • O’ Reilly, Yahoo Press
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JSON syntax rules
• Object data is in name/value pairs “firstName”:”John”
• JSON values
•A number (integer or floating point)
•A string (in double quotes) •A Boolean (true or false)
•An array (in square brackets) •An object (in curly braces) •null
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JSON syntax rules
• JSON Objects {“firstName”:”John”,
“lastName”:”Doe”}
• JSON Arrays “employees”:[
{“firstName”:”John”, “lastName”:”Doe”}, {“firstName”:”Anna”, “lastName”:”Smith”}, {“firstName”:”Peter”, “lastName”:”Jones”}
]
• These objects repeat recursively down a hierarchy as needed. • In terms of syntax that’s pretty much it!
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JSON format (from json.org)
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Verbosity
https://www.w3schools.com/js/js_json_xml.asp
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Python libraries for JSON and XML
• json • lxml
XML, JSON, CSV and HTML conversion tools
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JSON compared to XML
• JSON is simpler and more compact/lightweight than XML; easy to parse.
• Which appeals to programmers looking for speed and efficiency
• Widely used for storing data in noSQL databases
• Common JSON application – read and display data from a webserver using javascript. https://www.w3schools.com/js/js_json.asp
• XML comes with a large family of other standards for querying and transforming (XQuery, XML Schema, XPATH, XSLT, namespaces, …)
• allows formal validation
• makes you consider the data design more closely
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JSON: Summary
• JavaScript Object Notation
• Lightweight, streamlined, standard method of data exchange
• Originally designed to speed up client/server interactions: • By running in the client browser
• Can be used to represent any kind of semi structured data • Lacks context and schema definitions
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Break

Semi-structured Data – Cont.
PDF
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PDF – Portable Document Format
• A format for presenting documents independently of application software / OS
• Introduced by Adobe in 1993, standardized in 2008
• Large amounts of useful data stored in PDF format
(e.g. forms, invoices, etc.). Legacy data in particular.
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Challenges of PDF format
• Format is very flexible, limited consistency
• May contain different types of data; similar looking documents can be
represented very differently
• Text may be stored as images, e.g., for scanned documents
• Data is unstructured
• As a result, automated extraction is difficult
• May require substantial preprocessing to extract useable data © University of Melbourne 2021

Approaches to PDF data
Convert the PDF to text using a library (e.g. poppler, PDFMiner):
pdftotext nvsr65_05.pdf nvsr65_05.txt
!”#$%&”‘()$#”‘( *#”#$+#$,+(-./%0#+( )%’12.(345(!126.0(4(
71&.(895(:9;3(
<."#=+>(?.”@$&A(B”1+.+(C%0(:9;D( 6E(F.’%&$.(G.0%&5(H=I