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, ...

def get_name():
    """this function only returns arguments"""
    first = "Fred"
    last = "Ferkel"
    return first, last
 
def show_name(name):
    """this function only receives an argument"""
    print( name )
 
def process_name(first, last):
    """this function reveives 2 arguments, returns 1 argument"""
    name = "Mr. " + first +" " + last
    return name
 
def main():
    """
    this function handles the other functions in order
    and deals with the arguments received and to be passed
    """
    first, last = get_name()
    name = process_name(first, last)
    show_name(name)
 
# start the program with this function call
main()
 
"""my output -->
Mr. Fred Ferkel
"""

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...')
# with Python3 'raw_input()' has become 'input()'

# 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
"""

# exploring Python's slicing operator
# can be used with any indexed sequence like strings, lists, ...
# syntax --> seq[begin : end : step]
# step is optional
# defaults are index begin=0, index end=len(seq)-1, step=1
# -begin or -end --> count from the end backwards
# step = -1 reverses sequence
# if you feel lost, put in the defaults in your mind
 
# use a list as a test sequence
a = [0, 1, 2, 3, 4, 5, 6, 7, 8]
 
print( a[3:6] )   # [3,4,5]
# if either index is omitted, beginning or end of sequence is assumed 
print( a[:3] )    # [0,1,2]
print( a[5:] )    # [5,6,7,8]
 
# negative index is taken from the end of the sequence
print( a[2:-2] )  # [2,3,4,5,6]
print( a[-4:] )   # [5,6,7,8]
 
# extract every second element
print( a[::2] )   # [0, 2, 4, 6, 8]
 
# step=-1 will reverse the sequence
print( a[::-1] )  # [8, 7, 6, 5, 4, 3, 2, 1, 0]
 
# no indices just makes a copy (which is sometimes useful)
b = a[:]
print( b )    # [0, 1, 2, 3, 4, 5, 6, 7, 8]
 
# slice in (replace) an element at index 3
b[3:4] = [100]
print( b )    # [0, 1, 2, 100, 4, 5, 6, 7, 8]
# make another copy, since b has changed
b = a[:]
 
# slice in (insert) a few elements starting at index 3
b[3:] = [9, 9, 9, 9] + b[3:]
print( a )    # [0, 1, 2, 3, 4, 5, 6, 7, 8]
print( b )    # [0, 1, 2, 9, 9, 9, 9, 3, 4, 5, 6, 7, 8]

# 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') )

# explore the Tkinter GUI toolkit
 
 try:
    # for Python2
    import Tkinter as tk
except ImportError:
    # for Python3
    import tkinter as tk
 
# create a window frame 
frame1 = tk.Tk() 
# create a label 
label1 = tk.Label(frame1, text="Hello, world!") 
# pack the label into the window frame
label1.pack() 
 
frame1.mainloop()  # run the event-loop/program

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)  # input(prompt) in Python3
        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 )

# use module datetime to show age in days
# modified to work with Python2 and Python3
 
import datetime as dt
 
prompt = "Enter your birthday (format = mm/dd/yyyy): "
try:
    # Python2
    bd = raw_input(prompt)
except NameError:
    # Python3
    bd = input(prompt)
 
# split the bd string into month, day, year
month, day, year = bd.split("/")
 
# convert to format datetime.date(year, month, day))
birthday = dt.date(int(year), int(month), int(day))
 
# get todays date
today = dt.date.today()
 
# calculate age since birth
age = (today - birthday)
 
print( "You are %d days old!" % age.days )

# 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