Python Shallow Vs Deep Copy

import copy

#Shallow Copy
#   copy.copy(x)
#   A shallow copy creates a new object which stores the reference of the original elements.
#   A shallow copy doesn't create a copy of nested objects, instead it just copies the reference of nested objects. 

#Deep Copy
#   copy.deepcopy(x)
#   A deep copy creates a new object and recursively adds the copies of nested objects present in the original elements.


print ' --------- Copy by Ref ------ '
dic1 = {'StudnetId': 'test1', 'Scores': [60,70,80,90,85,45]}
dic2 = dic1

print dic1
print dic2

print 'Updating/Appending score 50'
dic1['Scores'].append(50) #update existing

print dic1 #{'StudnetId': 'test1', 'Scores': [60, 70, 80, 90, 85, 45]}
print dic2 #{'StudnetId': 'test1', 'Scores': [60, 70, 80, 90, 85, 45]}

#Both dic1 & dic2 point to same memory locations
print id(dic1) #46138688
print id(dic2) #46138688

print 'Adding new field Age'
dic1['Age'] = 25

print dic1 #{'Age': 25, 'StudnetId': 'test1', 'Scores': [60, 70, 80, 90, 85, 45, 50]}
print dic2 #{'Age': 25, 'StudnetId': 'test1', 'Scores': [60, 70, 80, 90, 85, 45, 50]}

print ' --------- Shallow Copy ------ '
dic1 = {'StudnetId': 'test1', 'Scores': [60,70,80,90,85,45]}
dic2 = copy.copy(dic1)

print dic1 #{'StudnetId': 'test1', 'Scores': [60, 70, 80, 90, 85, 45]}
print dic2 #{'StudnetId': 'test1', 'Scores': [60, 70, 80, 90, 85, 45]}

print "Memory locations of dic1 & dic2 respectively"
#Both dic1 & dic2 point to different memory location
print id(dic1) #57641696
print id(dic2) #57641840

print 'Updating/Appending score 50'
#Updating the existing will 
dic1['Scores'].append(50) #update existing

#Both dic1 & dic2 point to different memory locations
print dic1 #{'StudnetId': 'test1', 'Scores': [60, 70, 80, 90, 85, 45, 50]}
print dic2 #{'StudnetId': 'test1', 'Scores': [60, 70, 80, 90, 85, 45, 50]}

#Shallow Copy -> Internal data points to the same memory location
print "Memory locations of dic1['Scores'] & dic2['Scores'] respectively"
print id(dic1['Scores']) #52223472
print id(dic2['Scores']) #52223472

print 'Adding new field Age'
dic1['Age'] = 25

print dic1 #{'Age': 25, 'StudnetId': 'test1', 'Scores': [60, 70, 80, 90, 85, 45, 50]}
print dic2 #{'StudnetId': 'test1', 'Scores': [60, 70, 80, 90, 85, 45, 50]}

print ' --------- Deep Copy ------ '
dic1 = {'StudnetId': 'test1', 'Scores': [60,70,80,90,85,45]}
dic2 = copy.deepcopy(dic1)

#Both dic1 & dic2 point to different memory locations
print dic1 #{'StudnetId': 'test1', 'Scores': [60, 70, 80, 90, 85, 45]}
print dic2 #{'StudnetId': 'test1', 'Scores': [60, 70, 80, 90, 85, 45]}

print id(dic1) #54035776
print id(dic2) #54037504

print 'Updating/Appending score 50'
dic1['Scores'].append(50) #update existing

print dic1 #{'StudnetId': 'test1', 'Scores': [60, 70, 80, 90, 85, 45, 50]}
print dic2 #{'StudnetId': 'test1', 'Scores': [60, 70, 80, 90, 85, 45]}

print 'Adding new field Age'
dic1['Age'] = 25

print dic1 #{'Age': 25, 'StudnetId': 'test1', 'Scores': [60, 70, 80, 90, 85, 45, 50]}
print dic2 #{'StudnetId': 'test1', 'Scores': [60, 70, 80, 90, 85, 45]}

Learning Dictionary in Python

#!/usr/local/bin/python2.7

'''
#Learning Dictionary in Python
    File name: dict_all_operations.py
    Author: Prabhath Kota
    Date: June 22, 2018
    Python Version: 2.7
'''

'''
Python Dictionaries has key value pairs
They are not ordered
They don't have any index
Keys are unique
A key can be any type of objects, for example, a number, string in Python dictionary
Values can be accessed by using key rather than the index 
We can fetch the values by using key
Case sensitive

[ 'clear', 'copy', 'fromkeys', 'get', 'has_key', 'items', 'iteritems', 'iterkeys', 'itervalues', 'keys', 'pop', 'popitem', 'setdefault', 'update', 'values', 'viewitems', 'viewkeys', 'viewvalues']
'''
from copy import deepcopy
import operator

employees = {1000: {'name': 'Sahasra','country': 'India', 'age': 25}, \
1001: {'name': 'Peter','country': 'US', 'age': 21}, \
1002: {'name': 'John','country': 'US', 'age': 36}, \
1003: {'name': 'Sarayu','country': 'India', 'age': 30},\
1004: {'name': 'Akio','country': 'Japan', 'age': 60}, \
1005: {'name': 'Anand','country': 'India', 'age': 50}, \
1006: {'name': 'Vidya','country': 'India', 'age': 32}, \
1007: {'name': 'Salma','country': 'Bangladesh', 'age': 23},}
print employees

#{1000: {'country': 'India', 'age': 25, 'name': 'Sahasra'}, 1001: {'country': 'US', 'age': 21, 'name': 'Peter'}, 1002: {'country': 'US', 'age': 36, 'name': 'John'}, 1003: {'country': 'India', 'age': 30, 'name': 'Sarayu'}, 1004: {'country': 'Japan', 'age': 60, 'name': 'Akio'}, 1005: {'country': 'India', 'age': 50, 'name': 'Anand'}, 1006: {'country': 'India', 'age': 32, 'name': 'Vidya'}, 1007: {'country': 'Bangladesh', 'age': 23, 'name': 'Salma'}}

print '---------------Dictionary Keys---------------'
print employees.keys() #Get employee Ids
#[1000, 1001, 1002, 1003, 1004, 1005, 1006, 1007]

print '---------------Dictionary Values---------------'
print employees.values()
#[{'country': 'India', 'age': 25, 'name': 'Sahasra'}, {'country': 'US', 'age': 21, 'name': 'Peter'}, {'country': 'US', 'age': 36, 'name': 'John'}, {'country': 'India', 'age': 30, 'name': 'Sarayu'}, {'country': 'Japan', 'age': 60, 'name': 'Akio'}, {'country': 'India', 'age': 50, 'name': 'Anand'}, {'country': 'India', 'age': 32, 'name': 'Vidya'}, {'country': 'Bangladesh', 'age': 23, 'name': 'Salma'}]

print '---------------Dictionary Access---------------'
print employees[1002]
#{'country': 'US', 'age': 36, 'name': 'John'}
employee_obj = employees[1002]
print employee_obj['name']
#John
print employee_obj['country']
#US
print employee_obj['age']
#36
#print employee_obj['salary'] #This will throw error
print employee_obj.get('salary') #Get will return None atleast, but won't throw any error

print '---------------Dictionary Check if key exists---------------'
print 1002 in employees
#True
print 2002 in employees.keys()
#False
print employees.has_key('dept')
#None

print '---------------Dictionary Add/update---------------'
print employees
employees[1008] = {'name': 'Sriya','country': 'India', 'age': 42}

print employees.keys()
#[1008, 1000, 1001, 1002, 1003, 1004, 1005, 1006, 1007]

employees.update({1009: {'name': 'Ahmad','country': 'Bangladesh', 'age': 60}})
print employees.keys()
#[1008, 1009, 1000, 1001, 1002, 1003, 1004, 1005, 1006, 1007]

print '---------------Dictionary Delete entry---------------'
print employees.keys()
#[1008, 1009, 1000, 1001, 1002, 1003, 1004, 1005, 1006, 1007]

del employees[1009]

print employees.keys()
#[1008, 1000, 1001, 1002, 1003, 1004, 1005, 1006, 1007]

print employees[1002]
#{'country': 'US', 'age': 36, 'name': 'John'}

del employees[1002]['age']

print employees[1002]
#{'country': 'US', 'name': 'John'}

print employees[1002].pop('country') #You need to specify key name
#US

print employees[1002]
#{'name': 'John'}

print '---'
print employees[1002].popitem() #It randomly removed any one key
#('name', 'John')

print '---'
print employees[1002]
#{}

print '---'
print len(employees)
#9
del employees[1002]

print len(employees)
#8

print '---------------Dictionary copy by ref---------------'
print employees[1008]['age']
employees_1 = employees
employees[1008]['age'] = 45
print employees[1008]['age']
print employees_1[1008]['age']
#42
#45
#45

print '---------------Dictionary shallow copy---------------'
print employees[1008]['age']
employees_1 = employees.copy()
employees[1008]['age'] = 50
print employees[1008]['age']
print employees_1[1008]['age']
#45
#50
#50

print '---------------Dictionary deep copy---------------'
print employees[1008]['age']
employees_1 = deepcopy(employees)
employees[1008]['age'] = 55
print employees[1008]['age']
print employees_1[1008]['age']
#50
#55
#50

print '---------------Dictionary loop---------------'
for key,val in employees.items():
    print key, ' ----> ', val
for key in employees:
    print key, ' ----> ', employees[key]

#1008  ---->  {'country': 'India', 'age': 55, 'name': 'Sriya'}
#1000  ---->  {'country': 'India', 'age': 25, 'name': 'Sahasra'}
#1001  ---->  {'country': 'US', 'age': 21, 'name': 'Peter'}
#1003  ---->  {'country': 'India', 'age': 30, 'name': 'Sarayu'}
#1004  ---->  {'country': 'Japan', 'age': 60, 'name': 'Akio'}
#1005  ---->  {'country': 'India', 'age': 50, 'name': 'Anand'}
#1006  ---->  {'country': 'India', 'age': 32, 'name': 'Vidya'}
#1007  ---->  {'country': 'Bangladesh', 'age': 23, 'name': 'Salma'}


print '---------------Dictionary sort by key---------------'
for key in sorted(employees):
    print key, ' ----> ', employees[key]

#1000  ---->  {'country': 'India', 'age': 25, 'name': 'Sahasra'}
#1001  ---->  {'country': 'US', 'age': 21, 'name': 'Peter'}
#1003  ---->  {'country': 'India', 'age': 30, 'name': 'Sarayu'}
#1004  ---->  {'country': 'Japan', 'age': 60, 'name': 'Akio'}
#1005  ---->  {'country': 'India', 'age': 50, 'name': 'Anand'}
#1006  ---->  {'country': 'India', 'age': 32, 'name': 'Vidya'}
#1007  ---->  {'country': 'Bangladesh', 'age': 23, 'name': 'Salma'}
#1008  ---->  {'country': 'India', 'age': 55, 'name': 'Sriya'}

print '---------------Dictionary sort by value ---------------'
try:
   #Dictionary of Dictionaries - sort of specific value    
   print sorted(employees.items(), key=lambda(x,y): y['age'])
   #[(1001, {'country': 'US', 'age': 21, 'name': 'Peter'}), (1007, {'country': 'Bangladesh', 'age': 23, 'name': 'Salma'}), (1000, {'country': 'India', 'age': 25, 'name': 'Sahasra'}), (1003, {'country': 'India', 'age': 30, 'name': 'Sarayu'}), (1006, {'country': 'India', 'age': 32, 'name': 'Vidya'}), (1005, {'country': 'India', 'age': 50, 'name': 'Anand'}), (1008, {'country': 'India', 'age': 55, 'name': 'Sriya'}), (1004, {'country': 'Japan', 'age': 60, 'name': 'Akio'})]

   #Based on Value
   x = {1: 2000, 3: 8000, 4: 2500, 2: 9000, 9:10000, 7:9500}
   print x
   #{1: 2000, 2: 9000, 3: 8000, 4: 2500, 7: 9500, 9: 10000}

   sorted_x = sorted(x.items(), key=operator.itemgetter(1))
   print sorted_x
   #[(1, 2000), (4, 2500), (3, 8000), (2, 9000), (7, 9500), (9, 10000)]

   sorted_x = sorted(x.items(), key=lambda(x,y): y)
   print sorted_x
   #[(1, 2000), (4, 2500), (3, 8000), (2, 9000), (7, 9500), (9, 10000)]
except Exception, e:
   print e    

Learning lists - all operations

#!/usr/local/bin/python2.7

'''
    File name: list_all_operations.py
    Author: Prabhath Kota
    Date: June 22, 2018
    Python Version: 2.7
'''

freedom_fighters = ["Lala Lajipati Rai", "Dadabhai Naoroji", "Rajendra Prasad", "Sarojini Naidu", "Dadabhai Naoroji", "Lal Bahadur Shastri"]
print freedom_fighters
#['Lala Lajipati Rai', 'Dadabhai Naoroji', 'Rajendra Prasad', 'Sarojini Naidu', 'Dadabhai Naoroji', 'Lal Bahadur Shastri']

print '---------------index---------------'
print freedom_fighters[0]
print freedom_fighters[-1]
print freedom_fighters[2:]
print freedom_fighters[:-1]
print freedom_fighters[2:4]

#Lala Lajipati Rai
#Lal Bahadur Shastri
#['Rajendra Prasad', 'Sarojini Naidu', 'Dadabhai Naoroji', 'Lal Bahadur Shastri']
#['Lala Lajipati Rai', 'Dadabhai Naoroji', 'Rajendra Prasad', 'Sarojini Naidu', 'Dadabhai Naoroji']
#['Rajendra Prasad', 'Sarojini Naidu']

print '---------------insert in index---------------'
freedom_fighters[2] = 'Subhash Chandra Bose'
print freedom_fighters
#['Lala Lajipati Rai', 'Dadabhai Naoroji', 'Subhash Chandra Bose', 'Sarojini Naidu', 'Dadabhai Naoroji', 'Lal Bahadur Shastri']

print '---------------Add Element append vs extend---------------'
print freedom_fighters
#Append - appends as a single item
freedom_fighters.append('Subhash Chandra Bose')
print freedom_fighters
freedom_fighters.pop()
freedom_fighters.append(['Subhash Chandra Bose', 'Lal Bahadur Shastri'])
print freedom_fighters
freedom_fighters.pop()
#Extend - it adds multiple values
freedom_fighters.extend(['Subhash Chandra Bose', 'Lal Bahadur Shastri'])
print freedom_fighters
freedom_fighters.pop()
freedom_fighters.pop()
print freedom_fighters

#['Lala Lajipati Rai', 'Dadabhai Naoroji', 'Subhash Chandra Bose', 'Sarojini Naidu', 'Dadabhai Naoroji', 'Lal Bahadur Shastri']
#['Lala Lajipati Rai', 'Dadabhai Naoroji', 'Subhash Chandra Bose', 'Sarojini Naidu', 'Dadabhai Naoroji', 'Lal Bahadur Shastri', 'Subhash Chandra Bose', ['Subhash Chandra Bose', 'Lal Bahadur Shastri']]
#['Lala Lajipati Rai', 'Dadabhai Naoroji', 'Subhash Chandra Bose', 'Sarojini Naidu', 'Dadabhai Naoroji', 'Lal Bahadur Shastri', 'Subhash Chandra Bose', 'Subhash Chandra Bose', 'Lal Bahadur Shastri']
#['Lala Lajipati Rai', 'Dadabhai Naoroji', 'Subhash Chandra Bose', 'Sarojini Naidu', 'Dadabhai Naoroji', 'Lal Bahadur Shastri']

print '---------------Remove Element by value---------------'
print freedom_fighters
freedom_fighters.remove('Subhash Chandra Bose')
print freedom_fighters

#['Lala Lajipati Rai', 'Dadabhai Naoroji', 'Subhash Chandra Bose', 'Sarojini Naidu', 'Dadabhai Naoroji', 'Lal Bahadur Shastri']
#['Lala Lajipati Rai', 'Dadabhai Naoroji', 'Sarojini Naidu', 'Dadabhai Naoroji', 'Lal Bahadur Shastri']

print '-----------delete by index---------------------'
print freedom_fighters
del freedom_fighters[-1] #removes index element
del freedom_fighters[1] #removes index element
print freedom_fighters

#['Lala Lajipati Rai', 'Dadabhai Naoroji', 'Sarojini Naidu', 'Dadabhai Naoroji', 'Lal Bahadur Shastri']
#['Lala Lajipati Rai', 'Sarojini Naidu', 'Dadabhai Naoroji']

print '---------------By Ref---------------'
print freedom_fighters

#copy by Reference
freedom_fighters_1 = freedom_fighters
freedom_fighters_1.append('Bhagat Singh')
print freedom_fighters
print freedom_fighters_1

#['Lala Lajipati Rai', 'Sarojini Naidu', 'Dadabhai Naoroji']
#['Lala Lajipati Rai', 'Sarojini Naidu', 'Dadabhai Naoroji', 'Bhagat Singh']
#['Lala Lajipati Rai', 'Sarojini Naidu', 'Dadabhai Naoroji', 'Bhagat Singh']

print '---------------By Value -----------'
#copy by value
freedom_fighters_2 = freedom_fighters[:]
freedom_fighters_2.append('Sardar Vallabhbhai Patel')
print freedom_fighters
print freedom_fighters_2

#['Lala Lajipati Rai', 'Sarojini Naidu', 'Dadabhai Naoroji', 'Bhagat Singh']
#['Lala Lajipati Rai', 'Sarojini Naidu', 'Dadabhai Naoroji', 'Bhagat Singh', 'Sardar Vallabhbhai Patel']

print '---------------List Comprehension ---------------'

#This gives list
print [i + ' - India Salutes you' for i in freedom_fighters]

#tuple - gives generator object
generator_obj = (i + ' - India Salutes you' for i in freedom_fighters)
print generator_obj
for each in generator_obj:
print each

#['Lala Lajipati Rai - India Salutes you', 'Sarojini Naidu - India Salutes you', 'Dadabhai Naoroji - India Salutes you', 'Bhagat Singh - India Salutes you']
#<generator object <genexpr> at 0x0000000001EB41B0>
#Lala Lajipati Rai - India Salutes you
#Sarojini Naidu - India Salutes you
#Dadabhai Naoroji - India Salutes you
#Bhagat Singh - India Salutes you

print '---------------Sorted()---------------'
print freedom_fighters
print sorted(freedom_fighters)
print freedom_fighters

#['Lala Lajipati Rai', 'Sarojini Naidu', 'Dadabhai Naoroji', 'Bhagat Singh']
#['Bhagat Singh', 'Dadabhai Naoroji', 'Lala Lajipati Rai', 'Sarojini Naidu']
#['Lala Lajipati Rai', 'Sarojini Naidu', 'Dadabhai Naoroji', 'Bhagat Singh']

print '---------------list.reverse() ---------------'
print freedom_fighters
print freedom_fighters.reverse() #Returns None but reverse itself
print freedom_fighters

#['Lala Lajipati Rai', 'Sarojini Naidu', 'Dadabhai Naoroji', 'Bhagat Singh']
#None
#['Bhagat Singh', 'Dadabhai Naoroji', 'Sarojini Naidu', 'Lala Lajipati Rai']

print '---------------list.sort() ---------------'
print freedom_fighters
print freedom_fighters.sort() #Returns None but sorts itself
print freedom_fighters

#['Bhagat Singh', 'Dadabhai Naoroji', 'Sarojini Naidu', 'Lala Lajipati Rai']
#None
#['Bhagat Singh', 'Dadabhai Naoroji', 'Lala Lajipati Rai', 'Sarojini Naidu']

print '---------------multiply---------------'
freedom_fighters2 = freedom_fighters * 2
print freedom_fighters2
#['Bhagat Singh', 'Dadabhai Naoroji', 'Lala Lajipati Rai', 'Sarojini Naidu', 'Bhagat Singh', 'Dadabhai Naoroji', 'Lala Lajipati Rai', 'Sarojini Naidu']

print '---------------check if item exits---------------'
print freedom_fighters
print 'Bhagat Singh' in freedom_fighters
print 'Sardar Vallabhbhai Patel' in freedom_fighters

#['Bhagat Singh', 'Dadabhai Naoroji', 'Lala Lajipati Rai', 'Sarojini Naidu']
#True
#False

print '---------------Remove Duplicates---------------'
print freedom_fighters
freedom_fighters.append('Mahatma Gandhi')
freedom_fighters.append('Mahatma Gandhi')
print freedom_fighters
freedom_fighters_no_dup = []
[freedom_fighters_no_dup.append(x) for x in freedom_fighters if x not in freedom_fighters_no_dup]
print freedom_fighters_no_dup
print list(set(freedom_fighters)) #set - unordered collection data type, this kills the original order

#['Bhagat Singh', 'Dadabhai Naoroji', 'Lala Lajipati Rai', 'Sarojini Naidu']
#['Bhagat Singh', 'Dadabhai Naoroji', 'Lala Lajipati Rai', 'Sarojini Naidu', 'Mahatma Gandhi', 'Mahatma Gandhi']
#['Bhagat Singh', 'Dadabhai Naoroji', 'Lala Lajipati Rai', 'Sarojini Naidu', 'Mahatma Gandhi']
#['Mahatma Gandhi', 'Bhagat Singh', 'Lala Lajipati Rai', 'Dadabhai Naoroji', 'Sarojini Naidu']

print '---------------Convert to tuple---------------'
print freedom_fighters
print tuple(freedom_fighters)
print list(tuple(freedom_fighters))

#['Bhagat Singh', 'Dadabhai Naoroji', 'Lala Lajipati Rai', 'Sarojini Naidu', 'Mahatma Gandhi', 'Mahatma Gandhi']
#('Bhagat Singh', 'Dadabhai Naoroji', 'Lala Lajipati Rai', 'Sarojini Naidu', 'Mahatma Gandhi', 'Mahatma Gandhi')
#['Bhagat Singh', 'Dadabhai Naoroji', 'Lala Lajipati Rai', 'Sarojini Naidu', 'Mahatma Gandhi', 'Mahatma Gandhi']

print '---------------length of array---------------'
print freedom_fighters
print len(freedom_fighters) 

#['Bhagat Singh', 'Dadabhai Naoroji', 'Lala Lajipati Rai', 'Sarojini Naidu', 'Mahatma Gandhi', 'Mahatma Gandhi']
#6

print '---------------Find count of Element---------------'
freedom_fighters.append('Bhagat Singh')
print freedom_fighters
print freedom_fighters.count('Bhagat Singh')

#['Bhagat Singh', 'Dadabhai Naoroji', 'Lala Lajipati Rai', 'Sarojini Naidu', 'Mahatma Gandhi', 'Mahatma Gandhi', 'Bhagat Singh']
#2

print '---------------Pop---------------'
#pop() method removes and returns the last item if index is not provided
print freedom_fighters
freedom_fighters.pop()
print freedom_fighters

#['Bhagat Singh', 'Dadabhai Naoroji', 'Lala Lajipati Rai', 'Sarojini Naidu', 'Mahatma Gandhi', 'Mahatma Gandhi', 'Bhagat Singh']
#['Bhagat Singh', 'Dadabhai Naoroji', 'Lala Lajipati Rai', 'Sarojini Naidu', 'Mahatma Gandhi', 'Mahatma Gandhi']

print '---------------Insert---------------'
#When you insert(-3, 0) you are inserting 0 before index -3. 
#When it says "before" it has nothing to do with the direction of travel.
print freedom_fighters
freedom_fighters.insert(0,'Sarojini Naidu')
freedom_fighters.insert(len(freedom_fighters),'Sarojini Naidu')
print freedom_fighters
freedom_fighters.insert(-1,'Bhagat Singh')
print freedom_fighters
del freedom_fighters[0]
freedom_fighters.pop()
freedom_fighters.pop()
print freedom_fighters

#['Bhagat Singh', 'Dadabhai Naoroji', 'Lala Lajipati Rai', 'Sarojini Naidu', 'Mahatma Gandhi', 'Mahatma Gandhi']
#['Sarojini Naidu', 'Bhagat Singh', 'Dadabhai Naoroji', 'Lala Lajipati Rai', 'Sarojini Naidu', 'Mahatma Gandhi', 'Mahatma Gandhi', 'Sarojini Naidu']
#['Sarojini Naidu', 'Bhagat Singh', 'Dadabhai Naoroji', 'Lala Lajipati Rai', 'Sarojini Naidu', 'Mahatma Gandhi', 'Mahatma Gandhi', 'Bhagat Singh', 'Sarojini Naidu']
#['Bhagat Singh', 'Dadabhai Naoroji', 'Lala Lajipati Rai', 'Sarojini Naidu', 'Mahatma Gandhi', 'Mahatma Gandhi']

print '---------------Other Functions---------------'
#sorted(freedom_fighters)
#print max(freedom_fighters)
#print min(freedom_fighters)
#print sum(list1)