ONE SNIPPET PRO - PYTHON

One Snippet Pro is an initiative to learn and practice the programming in one snippet , We start learning a language or a technology using a simple hello world and we lean forward step by step to become a pro , But in this demo i am going to code it in to one snippet and cover as much as concepts possible. We have a lot of programming language and technologies in this series of "One Snippet Pro", The Post will have only two sections Simple introduction of the technology and One Snippet.

I am a big fan of game of thrones so most of the identifies , loops , destroying objects as a part of few snippets will have the logic play which you can relate to  Game of thrones.

You can email me at redhatvicky@gmail.com or twitter me at @rvigneshwaran88 for any queries ,suggestions and feedback. Would be very happy to take it.

Python :

Python is a general-purpose interpreted, interactive, object-oriented, and high-level programming language. It was created by Guido van Rossum during 1985- 1990. Like Perl, Python source code is also available under the GNU General Public License (GPL).

I have commit the same code in git , click here to get the git code

import time; #required inorder to use time module import calendar; #required inorder to use calender module

import math as mathInstance #user can import and rename and use the object

import os as osInstance #required inorder to use os module

import shutil as fileUtils #required in order to use high level file operations

import re as regexInstance #required in order to use regular expression

#Prints the content  (If you are running versions below 3)

#print "Hello, Python!"

#Prints the content (If you are running new version of Python)

print ("Hello World")

#Single and Multiline Commnets (All characters after the # and up to the end of the physical line is considered to be commented)

#print("Single line Comment")

#print("Multi Line Comment")

# ways of initializing the variables (5 Standard datatypes : Numbers,String,List,Tuple,Dictionary)

serialName = "Game of Thrones" #string data type

currentSeason = 7 #integer data type

averageDeathPerSeason = 177.57 #flating point datatype

gameOfThrones = aSongOfIceAndFire = createdBy = "George R. R. Martin" #multiLineAssignmnet

serialName,currentSeason,averageDeathPerSeason = " Game of Thrones ",7,177.57

# ways of concatinating and printing variables

print("Serial Name :: ",serialName," Current Season : ",currentSeason," Average Death Per Season : ",averageDeathPerSeason)

print(gameOfThrones,aSongOfIceAndFire)

# datatypes : Four types in the category numbers (int,long,float,complex)

# When user has multiline statements line continuation character (\) will solve the issue

total = "Game of Thrones " + \

"used seven writers " + \

"in six seasons"

print(total)

# datatypes : String

houseStark = 'EddardNedStark' #create String with single quote

houseStark = "EddardNedStark" #create String with double quote

#When we have multiple lines this triple quote is useful, we dont need a line contination character

houseStark = """EddardNedStark"""  #create String with triple quote

houseStark = '''EddardNedStark'''  #create String with triple quote

# Python allows negative indexing for its sequences,The index of -1 refers to the last item, -2 to the second last item and so on

print(houseStark)          # Prints full string

print(houseStark[0])      # Prints first character of the string

print(houseStark[-1])      # Prints last character of the string

print(houseStark[2:5])     # Prints characters starting from 3rd to 5th

print(houseStark[5:-2])   # Prints characters starting from 6th to 2nd last character

print(houseStark[2:])      # Prints string starting from 3rd character

print(houseStark * 2)     # Prints string two times

print(houseStark + "FROM WINTERFELL") # Prints concatenated string

print(houseStark * 2.5) #throws error "TypeError: string indices must be integers"

print(houseStark[125]) #throws error "IndexError: string index out of range"

print("Ned" in houseStark) #returns true if the string contains "Ned"

print("Ned" not in houseStark) #returns false as the string contains "Ned"

#Strings are immutable in python.

#houseStark[5] = 'a' #throws error "TypeError: 'str' object does not support item assignment"

#del my_string[1] #throws error "TypeError: 'str' object doesn't support item deletion"

#common python String methods

seasonOneEpisodeTwo = "the Kingsroad"

print(seasonOneEpisodeTwo.lower()) #Converts all uppercase letters in string to lowercase.

print(seasonOneEpisodeTwo.upper()) #Converts lowercase letters in string to uppercase.

print(seasonOneEpisodeTwo.split()) #Splits string according to delimiter str (space if not provided)

print("You#Win#or#You#Die".split("#")) #Splits string according to delimiter str (space if not provided)

print(" ".join(seasonOneEpisodeTwo)) #Merges (concatenates) the string representations of elements.

print(seasonOneEpisodeTwo.find('Kings')) #Determine if str occurs in string

print(seasonOneEpisodeTwo.capitalize()) #Capitalizes first letter of string

print(seasonOneEpisodeTwo.count("a")) #Counts how many times str occurs in string

print(seasonOneEpisodeTwo.endswith("road")) #Determines if string or a substring of string ends with suffix

print(seasonOneEpisodeTwo.isalnum()) #Returns true if string has at least 1 character and all characters are alphanumeric and false otherwise.

print(seasonOneEpisodeTwo.isalpha()) #Returns true if string has at least 1 character and all characters are alphabetic and false otherwise.

print(seasonOneEpisodeTwo.isdigit()) #Returns true if string contains only digits and false otherwise.

print(seasonOneEpisodeTwo.islower()) #Returns true if string has at least 1 cased character and all cased characters are in lowercase and false otherwise.

print(seasonOneEpisodeTwo.isnumeric()) #Returns true if a unicode string contains only numeric characters and false otherwise.

print(seasonOneEpisodeTwo.isspace()) #Returns true if string contains only whitespace characters and false otherwise.

print(seasonOneEpisodeTwo.istitle()) #Returns true if string is properly "titlecased" and false otherwise.

print(len(seasonOneEpisodeTwo)) #Returns the length of the string

print(max(seasonOneEpisodeTwo)) #Returns the max alphabetical character from the string seasonOneEpisodeTwo.

print(min(seasonOneEpisodeTwo)) #RReturns the min alphabetical character from the string seasonOneEpisodeTwo.

print(seasonOneEpisodeTwo.isdecimal()) #Returns true if a unicode string contains only decimal characters and false otherwise.

#pythonLists : similar to arrays but lists can hold items of hetrogeneous data type

listInstanceFirst = ["David Benioff & D. B. Weiss","Tim Van Patten"]

listInstanceSecond = ["Brian Kirk","Daniel Minahan","Alan Taylor"]

listConsolidated = listInstanceFirst + listInstanceSecond

nestedListInstance = ["Fire and Blood", ["Robb", "the king", "Jaime","captured by the Starks"], [10],'T'] #create a nested list

print(listInstanceFirst) #prints the whole list

print(listInstanceFirst[0]) #prints first element in the list

print(listInstanceFirst[-1]) #prints the last element in the list

print(listConsolidated[2:5])

print(listConsolidated[1:]) #prints from the elements starting from 2nd position

print(listConsolidated[:-5]) #prints from negining to the fourth

print(listConsolidated[:]) #prints element from beginning to the end

#add of delete any elements from the list

seasonOneEpisodesList = ["The Kingsroad","The Wolf and the Lion","A Golden Crown","You Win or You Die","The Pointy End",

"Baelor","Fire and Blood"]

seasonOneEpisodesList[0] = "Winter Is Coming" #insert in the respective index of the list

print(seasonOneEpisodesList)

seasonOneEpisodesList[1:4] = ["Lord Snow","Cripples, Bastards, and Broken Things"] #insert multiple items in position of the list

print(seasonOneEpisodesList)

seasonOneEpisodesList.append("The Kingsroad")

print(seasonOneEpisodesList)

seasonOneEpisodesList.append(["The Wolf and the Lion","A Golden Crown","You Win or You Die"])

print(seasonOneEpisodesList)

del seasonOneEpisodesList[0:2] # delete mltiple items in the list

print(seasonOneEpisodesList)

#More functions to manage a list

newListInstance = ['R','o','b','e','r','t','B','a','r','a','t','h','e','o','n']

newListInstance.remove('o') #removes the respective element from the list

print(newListInstance.pop(1)) #pops out respective element in the lisst

print(newListInstance.pop()) #pops out last element from the list

newListInstance.clear() # removes all the element from the list

print(newListInstance)

appendNewListInstance = ['H','a','m','m','e','r']

newListInstance.append(appendNewListInstance) # Add all elements of a list to the another list

print(newListInstance)

newListInstance.insert(4,appendNewListInstance) #Insert an item at the defined index

print(newListInstance)

print(appendNewListInstance.index('H')) #Returns the index of the first matched item

appendNewListInstance.sort()  #Sort items in a list in ascending order

print(appendNewListInstance)

appendNewListInstance.sort(reverse=True) #sort in descending order

print(appendNewListInstance)

newListInstance.reverse() #Reverse the order of items in the list

print(newListInstance)

print(newListInstance.copy()) #Returns a shallow copy of the list

#data type : Python Tuples : similar to the list but enclosed within parentheses.

# Tuple are immutable, iterating through tuple is faster than with list , write protected,

# Tuples that contain immutable elements can be used as key for a dictionary

tupleInstance = ()

tupleInstance = ("Catelyn Stark", "Sansa Stark", "Arya Stark","Robb Stark","Bran Stark")

tupleInstance = (22, "Jaime Lannister", 45)

tupleInstance = ("Viserys Targaryen", [82, 14, 63], (134, 221, 312))

tupleInstance = 3, 4.6, "Tyrion Lannister"

a, b, c = tupleInstance

print(a)

print(b)

print(c)

#creating tuple with one elements has a problem

tupleInstance = ("Cersei Lannister")

print(type(tupleInstance)) # this will result in the data type string <class 'str'>

tupleInstance = ("Daenerys Targaryen",)

print(type(tupleInstance)) # this will result in the data type tuple <class 'tuple'>

tupleInstance = "Jon Snow",

print(type(tupleInstance)) #this will result in the data type tuple <class 'tuple'>

# We can manage tuble as we manage the list

#additionals methods in a tuple

print(any(tupleInstance)) #Return True if any element of the tuple is true. If the tuple is empty, return False.

print(all(tupleInstance)) #Return True if all elements of the tuple are true (or if the tuple is empty).

print(len(tupleInstance)) #Return the length (the number of items) in the tuple.

print(max((82, 14, 63))) #Return the largest item in the tuple.

print(min((82, 14, 63))) #Return the smallest item in the tuple

print(sorted(tupleInstance)) #Take elements in the tuple and return a new sorted list (does not sort the tuple itself).

print(sum((82, 14, 63))) #             Retrun the sum of all elements in the tuple.

#Convert an iterable (list, string, set, dictionary) to a tuple.

print(tuple("Daenerys Targaryen"));

print(tuple(["Catelyn Stark", "Sansa Stark", "Arya Stark","Robb Stark","Bran Stark"]));

# data type : Dictionary : hash table type.

dictionaryInstance = {}

dictionaryInstance = {1: 'Winter Is Coming',2:'The Kingsroad',3:'Lord Snow'}

dictionaryInstance = {1: 'Winter Is Coming','WinterIsComing':["White Walkers","Eddard Ned Stark","Jon Arryn"

"King Robert Baratheon"]}

print(dictionaryInstance.get('WinterIsComing')) #using get to access elements

print(dictionaryInstance['WinterIsComing']) # directing acces using the key in dictionary

#create dictionary using the dict command

dictionaryInstance = dict({6:'A Golden Crown', 7:'You Win or You Die',8:'The Pointy End',9:'Baelor',10:'Fire and Blood'})

print(dictionaryInstance.get(7))

dictionaryInstance = dict([(4,'Cripples, Bastards, and Broken Things'), (5,'The Wolf and the Lion')])

print(dictionaryInstance[5])

# To print keys and values of the dictionary

print(dictionaryInstance.keys())   # Prints all the keys of the disctionary

print(dictionaryInstance.values()) # Prints all the values of the disctionary

#Arthimatic operators  a**b (exponential (power)) a//b (Floor Division)

a,b = 10,20

print(" a+b :",(a+b)," a–b :",(a-b)," a*b :",(a* b)," b/a :",(b / a)," b%a :",(b % a)," a**b :",(a**b)," a//b : ",a//b)

#Comparison Operators

print(" a == b :",(a == b)," a > b :",(a > b)," a < b :",(a < b)," a >= b :",(a >= b)," a <= b :",(a <= b))

#Bitwise Operators

print(" a & b :",(a & b)," a | b :",(a | b)," a ^ b :",(a ^ b)," ~a :",(~a)," a << 2 :",(a << 2)," a >> 2 :",(a >> 2))

#Membership Operators

listInstanceMem = [21,45,67,78,54,32]

print (75 in listInstanceMem) #Evaluates to true if it finds a variable in the specified sequence and false otherwise.

print (71 not in listInstanceMem) #Evaluates to true if it does not find a variable in the specified sequence and false otherwise.

#Identity Operators

print (a is b) #Evaluates to true if the variables on either side of the operator point to the same object and false otherwise.

print (a is not b) #Evaluates to false if the variables on either side of the operator point to the same object and true otherwise.

# Flow Control : if and else

# if Clause

king = "Robert Baratheon"

if king.endswith("Baratheon"):

print("Yes,He is a baratheon")

print("This is a common block which is printed always")

#if else and elif

if king.endswith("Targaryen"):

print("Yes,He is a Targaryen")

elif king.endswith("Stark"):

print("Yes,He is a stark")

elif king.endswith("Baratheon"):

print("Yes,He is a baratheon")

else:

print("random people in got")

#Flow Control : for loop

stark = ["Catelyn Stark", "Sansa Stark", "Arya Stark","Robb Stark","Bran Stark"]

for indv in stark:

print("Pointer is at :: ",indv)

print(range(10)) # generates sequence of numbers using range function

print(list(range(10))) # sets the range of numbers from 0 to 9 in a List and prints it

print(list(range(1,10))) # sets the range of numbers from index 1 to 9 in a List and prints it

print(list(range(2, 20, 3))) #firstParamter(2)=start,secondParamter(20)=stop,thirdParameter(3)=step

#using ranges to determine the length

for indv in  range(len(stark)):

print("Pointer is at :: ",indv," value is : ",stark[indv])

#use for with else : "Else is executed when there is no break in the for loop"

for indv in range(len(stark)):

print("killing :: ",stark[indv])

else:

print("No starks left to kill !!! Red Wedding " )

# Flow control : While Loop

# While with optional else (The else part is executed if the condition in the while loop evaluates to False)

totalNumber,sumOfItems,index = 10,0,1

while index <= totalNumber:

sumOfItems = sumOfItems + index

index = index+1

else:

print("Conditional false else")

print("The sumOfItems is", sumOfItems)

#Time functions

timeInstance = time.localtime(time.time())

print("Local current time :", timeInstance)

#Formattng Time according to the user requirement

timeInstance = time.asctime(time.localtime(time.time()) )

print("Local current time :", timeInstance)

#To Display calender of the respective month

calenderInstance = calendar.month(2017, 2)

print(calenderInstance)

# Function is a group of related statements that perform a specific task

# Function creation (def is a keyword) def functionname(parameter1,parameter2):

def greet(name):

"""This content is a docstring,generally docstrings are

enclosed within triple quoteswhich can extend

up to multiple lines , this is strored in __doc__

attribute"""

print("Good morning ",name)

greet("Samwell Tarly")

# docstring attribute with method call

print(greet.__doc__)

# if we dont provide arguement to the method it results in TypeError, but we can provide default arguements

def greet(name, msg = "Good morning !!! "):

print(msg + name)

greet("Samwell Tarly ","Good Noon !!! ")

greet("Samwell Tarly ")

#anonymous function : function without a name (represented using a keyword called lambda)

# will use the same function greet as the anonymous function

sendGreetings = lambda name : print ("Good Morning !!! ",name)

sendGreetings("Samwell Tarly ")

# Usage of map and Filter with anonymous functions

listRangeInstance = list(range(10))

filteredListinstance = list(filter(lambda x: (x%2 == 0),listRangeInstance))

mapListinstance = list(map(lambda x: x^2,listRangeInstance))

print("Map Applied Value ::",mapListinstance,"Filter Applied Value : ",filteredListinstance)

# Usage of variable arguements in a function

def sumOfItems(operation="add",*objectList):

sum = 0

for index in objectList :

sum = sum + index

print("The Sum of all elements in the list is :: ",sum)

#ret accessed globally from that function.

print(globals())

#If locals() is called from within a function, it will return all the names that can be accessed locally from that function.

print(locals())

sumOfItems("add",10,20,30) # this will yield the sum as 60

sumOfItems("add",10,20,30,40) #this will yield the sum as 100

#Mathematical Functions

print(mathInstance.pi) #mathematical Constant

print(mathInstance.factorial(22)) # factorial of a number

print(mathInstance.sqrt(225)) #factorial of a number

print(mathInstance.isnan(22)) #check whether its a number or not

print(mathInstance.exp(2)) #exponent function

print(mathInstance.e) #mathematical Constant

#The dir() built-in function returns a sorted list of strings containing the names defined by a module.

print(dir(calendar))

#Basic File Operations and exceptions

try:

fileInstance = open("test.txt",encoding = 'utf-8')

#Read the file line by line

for lineReader in fileInstance :

print(lineReader, end = '')

#method reads a file till the newline, including the newline character.

print(fileInstance.readlines())

finally:

fileInstance.close()

#Alternative way to open a file using "with" keyword,We don't need to explicitly call the close() method.

with open("pythonTags.txt",encoding = 'utf-8') as fileInstance:

print(fileInstance.read()) #Read the contends in the file

print(fileInstance.read(4)) #Read the first 4 data

print(fileInstance.tell()) #Get the current file position

print(fileInstance.seek(0)) #Bring the cursor to the zeroth position

print(fileInstance.name) #get the fileName from the file instance

print(fileInstance.closed) # to Know whethre the file is closed or not

print(fileInstance.mode) # to Know the opening mode of the file

#Directory Operations

print(osInstance.getcwd()) # get the current working directory

print(osInstance.getcwdb()) # get the current working directory as byte object

#osInstance.chdir("C:\\")

#print(osInstance.getcwd()) #printing after changing the directory

print(osInstance.listdir()) # to list all the directoris and files

#osInstance.mkdir('test') #make a new directory

#osInstance.rename('test','modfied') rename a directory

#osInstance.remove('test.txt') #to remove a file

#osInstance.rmdir('modfied') #to remove a directory

#fileUtils.rmtree('test') #Delete an entire directory tree;

class Playaround:

"""This is a docString for class, we can access using

__doc__ attribute"""

def __init__(self,firstNum=10,secondNum=10):

self.a = firstNum

self.b = secondNum

a,b = 20,30

def add(self):

print(a+b)

def greet(self):

print("Good Morning ,The Value of a is ",self.a,"The Value of b is ",self.b)

print("Playaround.a : ",Playaround.a,"Playaround.b : ",Playaround.b)

print("Playaround.add : ",Playaround.add) #call the method inside the class

print("Doc string of the class :: ",Playaround.__doc__) #display the doc string of the class

newObjectInstance = Playaround() # Object creation

print("The Value of a is ",newObjectInstance.a,"The Value of b is ",newObjectInstance.b)

print(newObjectInstance.add) #<bound method Playaround.add of <__main__.Playaround object at 0x004EA430>>

newObjectInstance.add() # method call from the object

newObjectInstance.greet() # method call from the object

#One More class Sample

class Targaryen:

count = 0

def __init__(self,name):

self.name = name

Targaryen.count += 1

def displayTargaryanCount(self):

print("The Count of the Targaryen is :: ",Targaryen.count)

def displayTargaryan(self):

print("The Targaryen is called :: ",self.name," Targaryen")

#Creating Objects

duncanInstance = Targaryen("Duncan")

rhaellaInstance = Targaryen("Rhaella")

aegonInstance = Targaryen("Aegon")

viserysInstance = Targaryen("Viserys")

#access using the object created

rhaegarInstance = Targaryen("Rhaegar")

rhaegarInstance.displayTargaryan()

# Manipulating attributes of an object

daenerysInstance = Targaryen("Daenerys")

print(hasattr(daenerysInstance, 'name')) # Returns true if 'name' attribute exists

print(getattr(daenerysInstance, 'name')) # Returns value of 'name' attribute

setattr(daenerysInstance, 'name', "Khaleesi") # Set attribute 'name' at Khaleesi

daenerysInstance.displayTargaryan()

#delattr(daenerysInstance, 'name') # Delete attribute 'age'

# Accessing the Glaobal varibale in the class

print("The Count of the Targaryen is ",Targaryen.count)

# More build in Attributes of the class

print("Targaryen.__doc__:", Targaryen.__doc__) #to get the class documentation

print("Targaryen.__name__:", Targaryen.__name__)  # to retrive the classname

print("Targaryen.__module__:", Targaryen.__module__) #to get the module name in which the class is defined

print("Targaryen.__dict__:", Targaryen.__dict__) #Dictionary containing the class's namespace.

#Inheritance #Stark Here is a Parent Class and Westeros is a Child Class

class Stark:

def __init__(self,firstName,secondName):

self.firstName = firstName

self.secondName = secondName

def displayFullName(self):

return self.firstName + " " +  self.secondName

class Westeros(Stark):

def __init__(self,firstName,secondName,placeName):

Stark.__init__(self,firstName,secondName) #refer the parent class init

self.placeName = placeName

def getDetails(self):

return "He is named :: ",self.displayFullName," from ",self.placeName

starkInstance = Stark("Ned","Stark")

print(starkInstance.displayFullName())

westerosInstance = Westeros("Catelyn","Stark","The Winterfell")

print(westerosInstance.getDetails())

#Regular Expression

inputLine = """Winterfell is the name given to the ancestral castle of House Stark.

It is built over a natural hot spring and the scalding water runs through the castle walls, warming halls and rooms."""

print(regexInstance.findall(r'is', inputLine)) # Find all instance of the word

matchInstance = regexInstance.search(r'is', inputLine) #Match the content any where

print(matchInstance.group(0))

#The match object can tell us the start and end indexes also here below is the sample

print(matchInstance.start())

print(matchInstance.end())

# parse by groups

westerosInformation = 'Essos, Climate: Mediterranean climate'

matchInstance = regexInstance.search(r'(\w+), (\w+): (\S+)', westerosInformation)

print("matchInstance.group(1) :: ",matchInstance.group(1))

print("matchInstance.group(2) :: ",matchInstance.group(2))

print("matchInstance.group(3) :: ",matchInstance.group(3))

# we can use find all with this snippet

print(regexInstance.findall(r'(\w+), (\w+): (\S+)', westerosInformation))

# we can set a name to that group and access by the name

matchInstance = regexInstance.search(r'(?P<placeInWesteros>\w+), (?P<type>\w+): (?P<info>\S+)', westerosInformation)

print("matchInstance.group(1) :: ",matchInstance.group("placeInWesteros"))

print("matchInstance.group(2) :: ",matchInstance.group("type"))

print("matchInstance.group(3) :: ",matchInstance.group("info"))

# Iterators two methods __iter__() and __next__()

westerosList = ["The North ","Winterfell","The Iron Islands","The Riverlands","The Stormlands"]

iteratorInstance = iter(westerosList)

while True:

try:

pointer = next(iteratorInstance)

print(pointer)

except StopIteration:

break