Learning Processing: A Beginner's Guide to Programming Images ...

344 Learning Processing
18.7
return true;
} else {
return false;
}
}
}
Beginner XML
Th e examples in Section 18.4 demonstrated the process of manually searching through text for individual
pieces of data. Admittedly, manually parsing the raw XML data from http://xml.weather.yahoo.com/
forecastrss?p � 10003 was not the most effi cient strategy. Yes, if you need information from an oddly
formed HTML page, these manual techniques are required. However, because XML is designed to
facilitate the sharing of data across diff erent systems, it can be parsed without manual searching, using an
XML parsing library.
XML organizes information in a tree structure. Let’s imagine a list of students. Each student has an id
number, name, address, e-mail, and telephone number. Each student’s address has a city, state, and zip
code. An XML tree for this dataset might look like Figure 18.12 .
Student Student Student Student
fi g. 18.12
Students
Th e XML source itself (with two students listed) is:
id name phone e-mail address
street city state zip
� ?xml version = " 1.0 " encoding = " UTF-8 " ? �
� students �
� student �
� id � 001 � /id �
� name � Daniel Shiffman � /name �
� phone � 555-555-5555 � /phone �
� email � daniel@shiffman.net � /email �
� address �
� street � 123 Processing Way � /street �
� city � Loops � /city �
� state � New York � /state �
� zip � 01234 � /zip �
� /address �
� /student �