In Python, you can specify that certain statements are only to be processed if a specified condition is true. These statements are known as conditional statements. When a conditional statement can be processed more than once, it is called a loop.

If you have previous programming experience, conditional statements in Python will seem familiar to you:

# print the numbers from 1 to 10
i = 1
while i <= 10:
    print i
    if i == 5:
        print "Halfway there"
    elif i == 9:
        print "One more to go"
    i = i + 1

	There are two rules you must follow when creating a conditional statement. The first rule is that you must include a colon character (:) after the conditional expression: if patientid == 42113: The second rule is that the statements to be executed if the conditional expression is true must be indented using some combination of tab characters and spaces: if patientid == 42113: print "This statement is part of the conditional statement" print "So is this one" print "But this one isn't" In Python, unlike many programming languages, indenting is meaningful.

The following sections provide more details on the conditional statements and loops available in Python, and on the values defined for use in them: