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

Data Input 329
Th e reverse of split( ) is join( ). join( ) takes an array of Strings and joins them together into one long String.
Th e join( ) function also takes two arguments, the array to be joined and a separator . Th e separator can
either be a single character or a String of characters.
Consider the following array:
String[] lines = { " It", "was", "a", "dark", " and" , "stormy", "night." } ;
Using the � operator along with a for loop, we can join a String together as follows:
// Manual Concatenation
String onelongstring = " " ;
for (int i = 0; i < lines.length; i + + ) {
onelongstring = onelongstring + lines[i] + " ";
}
Th e join( ) function, however, allows us to bypass this process, achieving the same result in only one line
of code.
18.3
// Using Processing’s join()
String onelongstring = join(lines, " ");
Exercise 18-5: Split the following String into an array of fl oating point numbers and
calculate the average.
String floats = " 5023.23:52.3:10.4:5.9, 901.3---2.3 ";
float[] numbers = ________(________(________, "________"));
float total = 0;
for (int i = 0; i < numbers.length; i + + ) {
}
________ += ________;
float avg = ____________________;
Reading and Writing Text Files
Data can come from many diff erent places: web sites, news feeds, databases, and so on. When developing
an application that involves a data source, such as a data visualization, it is important to separate out the
logic for what the program will ultimately do with the data from the retrieval of the data itself.
In fact, while working out the visuals, it is especially useful to develop with “ dummy ” or “ fake ” data. In
keeping with our one-step-at-a-time mantra, once the meat of the program is completed with dummy
data, you can then focus solely on how to retrieve the actual data from the real source.