if Statement

if x < 0:
# Action 1
elif x == 0:
# Action 2
elif x == 1:
# Action 3
else:
# Action 4

for Statement

devices = ['computer', 'phone', 'printer']
for elements in devices:
print elements, len(elements)
# Output:


computer 8
phone 5
printer 7

range() Function

If you do need to iterate over a sequence of numbers, the built-in function range() comes in handy. It generates lists containing arithmetic progressions:

range(10)




# Output:




[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
range(5, 10)


# Output:




[5, 6, 7, 8, 9]
range(0, 10, 3)


# Output:

[0, 3, 6, 9]
range(-10, -100, -30)




# Output:


[-10, -40, -70]

To iterate over the indices of a sequence, combine range() and len() as follows:

sentence = ['Tom', 'is', 'a', 'nice', 'guy']
for i in range(len(sentence)):
print i, sentence[i]





# Output:


0 Tom
1 is
2 a
3 nice
4 guy

Defining Functions

We can create a function like follows:

def sum(a,b):    # returns a+b
return a+b

# Now call the function we just defined:
sum(2,43)


# Output:


45

 

Department of Electronic Systems | Aalborg University | Niels Jernes Vej 12 | DK-9220 Aalborg | Denmark
Phone: (+45) 9635 8695 | Fax (+45) 9815 1583 | E-mail ies(at)ies.aau.dk
Copyright © 2006 Department of Electronic Systems

Last update:02-10-2006