print "Hello Monty Python!"

str1 = "Hello Monty Python!"
# this is a comment
# notice you don't have to declare the variable type
print str1

str1 = "Hello Monty Python!"
# let's replace the M with Spam
str2 = str1.replace('M', 'Spam')
# one more Spam for the P
str3 = str2.replace('P', 'Spam')
# now look at the result
print str1
print str2
print str3

def function_name(arg1, arg2, ...):
    statement block
    return arg3, arg4, ... 

# a function to format to $ currency
def formatDollar(amount):
    return "$%.2f" % amount
 
print formatDollar(123.9 * 0.07)
print formatDollar(19)

def formatDollar(amount):
    """
    a function to format to $ currency
    (this allows for multiline comments)
    """
    return "$%.2f" % amount
 
print formatDollar(123.9 * 0.07)
print formatDollar(19)

# accessing the documentation string
# (these are double underlines around doc)
print formatDollar.__doc__

import math
 
def getDistance(x1, y1, x2, y2):
    """
    getDistance(x1, y1, x2, y2)
    returns distance between two points using the pythagorean theorem
    the function parameters are the coordinates of the two points
    """
    dx = x2 - x1
    dy = y2 - y1
    return math.sqrt(dx**2 + dy**2)
 
print "Distance between point(1,3) and point(4,7) is", getDistance(1,3,4,7)
print "Distance between point(1,3) and point(11,19) is", getDistance(1,3,11,19)
 
print '-'*50  # print 50 dashes, cosmetic
print "The function's documentation string:"
# shows comment between the triple quotes
print getDistance.__doc__

def getDistance(x1, y1, x2, y2):
    """
getDistance(x1, y1, x2, y2)
returns distance between two points using the pythagorean theorem
the function parameters are the coordinates of the two points
    """
    dx = x2 - x1
    dy = y2 - y1
    return math.sqrt(dx**2 + dy**2)

builtin_fuction_list = dir(__builtins__)
print builtin_fuction_list
 
print "-"*70  # print a decorative line of 70 dashes
 
# or each function on a line using a for loop
for funk in builtin_fuction_list:
    print funk
 
print "-"*70
 
# or each function on a line joining the list to a string
print '\n'.join(builtin_fuction_list)
 
print "-"*70
 
# or, a little more advanced, combine it all and do a case insensitive sort too
print '\n'.join(sorted(dir(__builtins__), key = str.lower))

from keyword import kwlist
 
print kwlist

# use slicing to spell a string in reverse 
 
str1 = "Winners never quit, quitters never win!"
# slicing uses [begin : end : step]
# end is exclusive
# defaults are begin = 0, end = len of string, step = 1
# use step = -1 to step from end 
print "reverse = ", str1[::-1]

# use slicing to spell a string in reverse 
 
str1 = "Winners never quit, quitters never win!"
# slicing uses [begin : end : step]
# end is exclusive
# defaults are begin = 0, end = len of string, step = 1
# use step = -1 to step from end 
print "reverse = ", str1[::-1]
 
# optional wait for keypress
raw_input('Press Enter...')

# slicing uses [start:<end:step]
 
s4 = "hippopotamus"
 
print "first 2 char = ", s4[0:2]
print "next 2 char  = ", s4[2:4]
print "last 2 char  = ", s4[-2:]
print "exclude first 3 char  = ", s4[3: ]
print "exclude last 4 char   = ", s4[:-4]
print "reverse the string    = ", s4[::-1]  # step is -1
print "the whole word again  = ", s4
print "spell skipping 2 char = ", s4[::2]  # step is 2
"""
my output -->
first 2 char =  hi
next 2 char  =  pp
last 2 char  =  us
exclude first 3 char  =  popotamus
exclude last 4 char   =  hippopot
reverse the string    =  sumatopoppih
the whole word again  =  hippopotamus
spell skipping 2 char =  hpooau
"""

# list all the modules Python currently knows about ...
help("modules")
 
# now pick a module from that list you want to know
# more about ...
 
# to get help about module calendar ...
help("calendar")
 
# dito for the math module
help("math")
 
# file stuff ...
help("file")
 
# down to method/function level ...
help("os.read")

# read a text file to a string and create a list of words
 
# use any text file you have ...
textf = open('xmas.txt', 'r')
str1 = textf.read()
textf.close()
 
print "The text file as one string:"
print str1
 
# splits at the usual whitespaces
wordlist = str1.split(None)
print "\nThe string as a list of words:"
print wordlist
 
print "\nThere are %d words in the list." % len(wordlist)

# a function to return the numeric content of a cost item
# for instance $12.99 or -$123456789.01 (deficit spenders)
def getVal(txt):
  if txt[0] == "$":    # remove leading dollar sign
    txt = txt[1:]
  if txt[1] == "$":    # could be -$xxx
    txt = txt[0] + txt[2:]
 
  while txt:           # select float or integer return
    try:
      f = float(txt)
      i = int(f)
      if f == i:
        return i
      return f
    except TypeError:  # removes possible trailing stuff  
        txt = txt[:-1]
  return 0
 
# test the function ...
print getVal('-$123.45')

# import all the Tkinter methods
from Tkinter import * 
 
# create a window frame 
frame1 = Tk() 
# create a label 
label1 = Label(frame1, text="Hello, world!") 
# pack the label into the window frame
label1.pack() 
 
frame1.mainloop()  # run the event-loop/program 

# raw_input() reads every input as a string
# then it's up to you to process the string
str1 = raw_input("Enter anything:")
print "raw_input =", str1
 
# input() actually uses raw_input() and then tries to
# convert the input data to a number using eval()
# hence you could enter a math expression
# gives an error if input is not numeric eg. $34.95
x = input("Enter a number:")
print "input =", x

print "The grade point average (GPA) calculator:"
 
def get_list(prompt):
    """
    loops until acceptable data or q (quit) is given
    returns a list of the entered data
    """
    data_list = []
    while True:
        sin = raw_input(prompt)
        if sin == 'q':
            return data_list
        try:
            data = float(sin)
            data_list.append(data)
        except ValueError:
            print "Enter numeric data!"
 
print
gp_list = get_list("Enter grade point (q to quit): ")
print gp_list  # test
# process the list ... 
# calculate the average (sum of items divided by total items)
gpa = sum(gp_list)/len(gp_list)
 
print "The grade point average is:", gpa

# Python's input() is mainly used for entering numbers
age = input("Enter your age: ")
print age
"""
for instance -->
25
"""
 
# however, you can enter a mathematical expression
result = input("Enter a mathematical expression: ")
print result
"""
for instance the user enters 7 * 7 -->
49
"""
 
# you can enter a complete list, tuple or dictionary using input
mylist = input("Enter a list: ")
print mylist, type(mylist)
"""
for instance -->
[1, 2, 3, 5] <type 'list'>
"""
 
# you can enter a string if you put it in quotes
mystring = input("Enter a string in quotes")
print mystring, type(mystring)
"""
for instance -->
hello <type 'str'>
"""
 
# you can enter and execute a python statement
code = input("Enter  __import__('calendar').prmonth(2007, 6) ")
"""
result -->
     June 2007
Mo Tu We Th Fr Sa Su
             1  2  3
 4  5  6  7  8  9 10
11 12 13 14 15 16 17
18 19 20 21 22 23 24
25 26 27 28 29 30
"""
 
# however, here is a potential problem
# let's say you declare
x = 777
# now you add more code here
# ...
# ...
# then you use a somewhat unclear input prompt
# and the user actually enters x rather than the value for x
xvalue = input("Enter x: ")
print xvalue
"""
an oops, if user enters x -->
777
"""

# use a tuple to return multiple items from a function
# a tuple is a set of values separated by commas
def multiReturn():
    return 3.14, "frivolous lawsuits", "Good 'N' Plenty"
 
# show the returned tuple
# notice that it is enclosed in ()
print multiReturn()
 
# load to a tuple of variables
num, str1, str2 = multiReturn()
print num
print str1
print str2
 
# or pick just the element at index 1, should be same as str1
# tuples start at index zero just like lists etc.
print multiReturn()[1]

# explore the argument tuple designated by *args
# used for cases where you don't know the number of arguments
def sum_average(*args):
    size = len(args)
    sum1 = sum(args)
    average = sum1/float(size)
    # return a tuple of three arguments
    # args is the tuple we passed to the function
    return args, sum1, average
 
# notice that the first element is the args tuple we send to the function
print sum_average(2, 5, 6, 7)  # ((2, 5, 6, 7), 20, 5.0)
 
# or unpack into a tuple of appropriate variables
args_tuple, sum2, average = sum_average(2, 5, 6, 7)
 
print "sum of %s = %d" % (args_tuple, sum2)  # sum of (2, 5, 6, 7) = 20
 
print "average of %s = %0.2f" % (args_tuple, average)  # average of (2, 5, 6, 7) = 5.00
 
# or just pick one return value, here value at index 1 = the sum
print "sum =", sum_average(2, 5, 6, 7)[1]  # sum = 20