Professional IronPython

LISTINg 3-4: 
 Making complex decisions
# Define an input variable.
Answer = raw_input(‘Say hello (Y/N)?’)
# Check the value of Answer.
if Answer.upper() == ‘Y’:
# Perform some tasks based on a positive response.
print ‘You typed:’, Answer
print ‘So Hello!’
# Check to see if the user entered N
elif Answer.upper() == ‘N’:
# Give a reponse for a negative answer.
print ‘Sorry to hear you don\‘t want to say hello.’
# The user must have typed something else.
else:
# Perform some tasks based on a different response.
print ‘You need to type Y or N!’
# Pause after the debug session.
raw_input(‘Press any key to continue...’)
LISTINg 3-3 
(continued)
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2/24/10 12:47:30 PM
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Creating Loops
 
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As you can see from the code, the 
elif
clause looks very much like the 
if
clause. The only differ-
ence is that the 
elif
clause must follow the 
if
clause. You can include as many 
elif
clauses as 
required to perform a particular task. The output from this example is similar to that shown in 
Figure 3-2.
CREATINg LooPS
Computers are far better at repetitive tasks than humans. A computer will perform the same task as 
long as you want it to. In fact, your computer is currently performing tasks repetitively, even if you 
didn’t start those tasks. For example, you probably have a firewall that’s looking for terrifying inputs 
from outside sources, using some type of repetitive procedure. Applications handle these repetitive 
tasks using loops. IronPython provides two kinds of loops as described in the following sections:
➤
for...in
➤
while
➤
➤