# prints numbers 0-4 on separate lines:
for i in range(5):
    print i

# also prints numbers 0-4 on separate lines:
for i in range(0,5):
    print i

# print is the python equivalent of printf.
# just join everything with commas.
print "This is a string with numbers", 1, ",", 2, ", and", 3

# you can also use print with interpolation, like printf's format string
# the '%' operator takes a format string and an tuple of values to interpolate
print "This is a string with numbers %d, %d, and %d" % (1,2,3)

# tuples in python are like immutable arrays in other languages
# declare and print a tuple with three elements
tuple = (1, 2, 3)
print tuple

# destructure tuple into three different variables
# verify that the values are what we think they are.
(one, two, three) = tuple
assert one == 1, "one is not 1!"
assert two == 2, "two is not 2!"
assert three == 3, "three is not 3!"

# here's another way to pull elements out of a tuple
one = tuple[0]
two = tuple[1]
three = tuple[2]
assert one == 1, "one is not 1!"
assert two == 2, "two is not 2!"
assert three == 3, "three is not 3!"

# tuples are readonly---you can't change a value in a tuple:
#tuple[1] = 4  # this would fail
#tuple[2] = 9  # this would fail

# here's a tuple with no (zero) elements
zeroElementTuple = ()
print "null tuple:", zeroElementTuple

# here's a tuple with one element
# the comma is necessary to make sure python knows this is a tuple
oneElementTuple = (1,)
print "one-element tuple:", oneElementTuple

# tuples can be concatenated with the '+' operator:
concatenatedTuple = oneElementTuple + oneElementTuple
assert concatenatedTuple == (1,1), "concatenation didn't work!"
print "Here's a concatenated tuple:", concatenatedTuple

# or the += operator:
concatenatedTuple += oneElementTuple
assert concatenatedTuple == (1,1,1), "concatenation didn't work!"
print "Here's a concatenated tuple:", concatenatedTuple

# concatenating the null tuple does what you'd expect
concatenatedTuple = () + concatenatedTuple + ()
assert concatenatedTuple == (1,1,1), "concatenation didn't work!"
print "Here's a concatenated tuple:", concatenatedTuple

# dictionaries are hash tables with some reasonable built-in hash function
dict = {}        # create an empty dictionary
dict[123] = 456
dict[789] = 0
dict['foo'] = 'bar'
assert dict[123] == 456, "value didn't match!"
assert dict[789] == 0, "value didn't match!"
assert dict['foo'] == 'bar', "value didn't match!"