#!/usr/bin/env python

# Number one thing to recognize: Python is a SPACE SENSITIVE language!!!
# Also, Python is an interpreted language, so the line at the top of this
# file is required.

# Variables are dynamically typed. 
x = 20
y = 1009.34531
z = "another variable"

# Strings like z are treated like strings of characters.
# If statements are still if statements.
if (z == 'another ' + 'variable'):
    print 'The two strings sure are the same!'
elif x == 20:
    print 'Whoops, guess I was wrong there!'

# Now let's create a list of random data types.
# Note how the floating point value 22.22 is displayed. 
list = ['alpha', 100, ['a','b','c'],22.22]
print '\nAnd the contents of the list:'
print list[0]
print list[1]
print list[2]
print list[3]
print 'The last element of the list is:' , list[-1]
print 'The first element of the list are:' , list[:1]
print 'The last two elements of the list are:' , list[2:]

# For statments are more like Perl For statements.
print '\nAnd again, but this time with a For loop'
for r in list:
    print r

# While statements are still while statements.
# Note the comma which allows for printing on the same line. This
# tells the interpreter that you haven't finished with the current line.
print 'Type the any key to continue.'
p = 10
while p > 0:
    print p,
    p -= 1

# Can you believe functions are simple too? And how about some user input?
# A function must be defined before use.
def a_function_for_you(a):
    input = raw_input('Type something: ')
    print 'You typed: "',input,'"'
    print 'And the argument the function received was: ',a

# Now we'll call the function
a_function_for_you('Python couldn\'t be easier')

# One more important thing, arguments in functions are passed by value,
# not reference.
def pass_by_reference(arg):
    print 'Inside function before:',arg
    arg = 99
    print 'Inside function after:',arg

num = 2
print 'Before:',num
pass_by_reference(num)
print 'After:',num

# And finally, we come to classes, which are just as simple as functions.
# Classes must also be defined before use.

class NewClass:
    a = 99
    # 'self' refers to the the class as a whole. This allows for accessing
    # other variables and functions from NewClass and defining new variables
    # that will be recognized throughout the class.

    # __init__ is the contructor function called upon initialization
    def __init__(self):
        self.data = []
    def print_variables(self):
        print self.a,self.data
    def define_data(self, var):
        self.data.append(var)

# Now we initialize the class and play with it.
# Note, 'a' is not a private variable. Making variables "private" is
# a little sketchy.
object = NewClass()
print object.a
object.print_variables()
object.define_data('blah')
object.print_variables()

# For more information on Python refer to tutorials on the net, there
# are some exceptionally good ones.