To display a value or the contents of a variable on your screen, use print. Here is a simple example:

greeting = "Hello, world!"
print greeting

This displays Hello, world! on your screen.

	This example is a complete working Python script. This script contains two lines of code: an assignment and a use of print. Each line of code is also referred to as a statement. To run this script on a standalone version of Python, save the script as a file with suffix .py, such as test.py. Then, in a command prompt or shell window, type the command python test.py. You should see Hello, world!.

You can use print to display more than one value at a time. For example:

msg = "The patient ID is"
patientid = 42113
print msg, patientid

This displays The patient ID is 42113. There are two things to notice in this program:

• print inserts a space between the two values it displays.
• You can use print to display either strings or numbers.

Normally, each print statement displays its output on a separate output line. If you want two print statements to display to the same output line, put a comma (,) at the end of the first print statement. For example:

msg = "The patient ID is"
patientid = 42113
print msg,
print patientid

Once again, this displays The patient ID is 42113.

When printing, you can use %s to include the contents of a variable:

patientid = 42113
print "The patient ID is %s" % patientid

This also displays The patient ID is 42113.

If you use %s to print more than one variable, Python processes them from left to right:

patientid1 = 42113
patientid2 = 42114
print "The patient IDs are %s and %s" % (patientid1, patientid2)

This displays The patient IDs are 42113 and 42114. If you supply more than one variable, you must enclose the list of variables in parentheses.

	Within Chameleon, you can use print to debug your Python scripts. For more information on debugging Python scripts, see Debugging Python.