### Introduction to Python examples

def nums1():
	"""Number Examples"""
	print "hello"
	print "0xFF = " + str(0xFF)
	print "0377 = " + str(0377)
	print
	print "1/2 = " + str(1/2)
	print "1.0/2.0 = " + str(1.0/2.0)
	print "float(1)/2 = " + str(float(1)/2)
	print
	print "2**100 = " + str(2**100)
	print
	print "1j**2 = " + str(1j**2)

def nums2(): 
	"""Why we use str in nums2"""
	print "0377 = " * 0377
	print 0xFF
	print "0xFF:" + 0xFF

def strings():
	"""String examples"""
	print "hello world"
	print "hello" + " " + "world"
	x = "hello world"
	print "x = " + x
	print "x[0] = " + x[0]
	print "x[10] = " + x[10]
	print "x[-1] = " + x[-1]
	print "j" + x[1:11] ## From 1 up to but not including 11
	print "Length of x is " + str(len(x))
	if("e" in x):
		print "e is in the string."
	else:
		print "e is not in the string."
	print '"'
	print "Usage\n\t-f filename\n\t-o output"
	print """Usage
	-f filename
	-o output"""

def lists():
	"""List Examples"""
	a = [99, "Bottles of Beer", ["on", "the", "wall"]]
	print "a = " + str(a)
	print "a[0] = " + str(a[0]) ## Must use str
	print "a[1] = " + a[1]
	print "a[2] = " + str(a[2]) ## Must use str
	print
	print "a[2][1:2] = " + str(a[2][1:3])
	print "a[2][1] + a[2][2] = " + a[2][1] + " " + a[2][2]
	print "len(a) = " + str(len(a))
	print
	print a
	a[0] = 98
	print a
	print
	print "a[1:2] = " + str(a[1:2])
	print a
	a[1:2] = ["Bottles", "Of", "Beer"]
	print a
	print
	print a
	a = [99, "Bottles of Beer", ["on", "the", "wall"]]
	print "a[1:3] = " + str(a[1:3])
	a[1:3] = ["Bottles", "Of", "Beer"]
	print a

def dictionaries(): 
	d = {"duck": "eend", "water": "pond"}
	print "d = " + str(d)
	print 'd["duck"] = ' + d["duck"]
	del d["water"]
	print
	print "d = " + str(d)
	d["back"] = "rug"
	d["duck"] = "duckling"
	print "d = " + str(d)
	print
	print "d.keys() = " + str(d.keys())
	print "d.values() = " + str(d.values())
	print "d.items() = " + str(d.items())
	print "d.items()[1] = " + str(d.items()[1])


def tuples():
	tup1 = ("hey", "you")
	tup2 = "hey", "you"
	a,b = tup2
	print "tup1 = " + str(tup1)
	print "tup2 = " + str(tup2)
	print "a = " + a
	print "b = " + b

class ClassVars (object):
	x = 5

	def setx1(self, y):
		self.x = y

	def setx2(self, y):
		ClassVars.x = y

	def getx1(self) :
		return self.x

	def getx2(self) :
		return ClassVars.x

def instanceVars():
	a = ClassVars()
	b = ClassVars()

	print "a.getx1 = " + str(a.getx1())
	print "a.getx2 = " + str(a.getx2())
	print "b.getx1 = " + str(b.getx1())
	print "b.getx2 = " + str(b.getx2())
	print

	b.setx2(10)

	print "a.getx1 = " + str(a.getx1())
	print "a.getx2 = " + str(a.getx2())
	print "b.getx1 = " + str(b.getx1())
	print "b.getx2 = " + str(b.getx2())
	print

	a.setx1(3)

	print "a.getx1 = " + str(a.getx1())
	print "a.getx2 = " + str(a.getx2())
	print "b.getx1 = " + str(b.getx1())
	print "b.getx2 = " + str(b.getx2())


def foo(x):
	return 1/x

def bar(x):
	try:
		print foo(x)
	except ZeroDivisionError, message:
		print "Can't divide by zero:", message

def files(filename):
	## Be aware \n are encoded into strings
	f = open(filename, "r")
	print "filename has " +str(f.fileno()) + " lines"
	for line in f:
		print line,

	f.seek(0,0)
	
	lines = f.readlines()
	print("lines = ") + str(lines)
	f.close()