• For

A "for" loop is one of the most common loops in programming; however, if you've done programming in langauges like C or Java, it is important to realize that "for" is used in Jython a little differently than in many other languages. A "for" loop in Jython tells the computer to do something for each element in a sequence.

In media computation, "for" loops are often used to change every sample in a sound file, or every pixel in a picture file, or every frame in a video file. You can make powerful for loops by combining them with the range function.

For example, if you wanted the computer to divide each number between 5 and 10 (not including 5 or 10), and print the results, you could use a "for" loop with the range function:

>>> for x in range(6,10):
...   print x/2.0
3.0
3.5
4.0
4.5

So we told the computer that for each number in the range six through 10, for x in range(6,10), divide it by 2.0 and print the result: print x/2.0

Notice that the body of the "for" statement--the part where we told it what to do print x/2.0--is indented.