Dictionaries:
=============
strings ==> quotes
	'python' or "python" or '''python'''
	str
list ==> []
	[1,2,3,4,5]
	list
tuple ==> ()
	(5,4,3,2,1)
	tuple
sets ==> {}
	{2,4,6,8,10}
	set


About Dictionaries:
===================
==> built-in class: dict

# How to create the dictionary
# empty dictionary

d1 = {}
# d2 = {1,2,3,4,5}
# dictionary is the collection of elements
# here: elements are the combination of key and value pair
# syntax: key : value
# Syntax of dictinary:
# {key1:value1,key2:value2,key3:value3,...}
# keys:
#-=====
# keys are strings or integers or floats or complex numbers or booleans
# values are strings or integers or floats or complex numbers or booleans

d2 = {'key1':'apple','key2':'banana','key3':'cherry','key4' : 'papaya'}
d3 = {101:'a',201:'b',301:'c',401:'d'}
d4 = {'a' : 1.001,'b' : 2.001,'c' : 3.001}

# keys of the dictionary must be unique. But values are not unique.
d5 = {'a' : 100,'b' : 200,'c' : 300, 'a' : 400}
# if the key is duplicated, the dictionary can be updated with latest key:value pair
d6 = {'a' : 100,'b' : 100,'c' : 100}

print(type(d1))
print(type(d2))
print(type(d3))
print(type(d4))

print(d5)
print(d6)

# using dict() also we can create the dictionary
d7 = dict({'apple' : 121,'banana' : 131,'cherry':144})

print(d7)

# run time/dynamic dictionary
# eval() and input()

d8 = eval(input("Enter a dictionary:"))

print(d8)

===========================================================
# Dictionary Properties

# Dictionary is ordered.

d1 = {'a':111,'b':222,'c':333,'d':444}

print(d1)

# dictionary never be an indexed.
# print(d1[0]) ==> key error
# to access the values of the dictionary
# we need to use "keys"
# syntax: dictionary-name[key-name]
print(d1['a'])
print(d1['b'])
print(d1['c'])
print(d1['d'])

# Keys of dictionary can be accessed using keys()
# values of dictionary can be accessed using values()

print(d1.keys())
print(d1.values())

for i in d1:
    # print(i)
    print(i,":",d1[i])

# items() ==> can return all the items of the dictionary
print(d1.items())

for i in d1.items():
    print(i)

# dictionary is mutable.

print(d1)
print(id(d1))

# modification
d1['c'] = 3333

print(d1)
print(id(d1))

d1['e'] = 1010
print(d1)
print(id(d1))

===================================================

# Dictionary aliasing and Cloning

d1 = {'a':111,'b':222,'c':333,'d':444,'e':555}

# aliasing
d2 = d1

print(id(d1))
print(id(d2))

d1['p'] = 666
print(d1)
print(d2)

# cloning
d3 = d1.copy()

print(id(d1))
print(id(d3))

d3['r'] = 7979

print(d1)
print(d3)
============================================
# update()
# dictionary-name.update(x)
# to extend the dictionary with another dictionary, we can use "extend()".

d1 = {'a':111,'b':222,'c':333}
d2 = {'d':444,'e':555,'f':666}

d1.update(d2)

print(d1)
print(d2)
=========================================================

# WAP TO ENTER NAME AND PERCENTAGE IN A DICTIONARY AND DISPLAY THE INFORMATION ON THE SCREEN.

record = {}
# student record ==> name and marks

n = int(input("Enter number of students:"))

i = 1
while i <= n:
    name = input("Enter the student name:")
    marks = input("Enter student marks:")
    record[name] = marks
    i += 1

print("Name of the student","\t","Marks of the student")
for key in record:
    print("\t",key,"\t\t\t\t",record[key])

==========================================================

d1 = {'a' : 11,'b' : 22,'c' : 33,'d' : 44,'e' : 55}

print(d1)

# pop() ==> dict-name.pop(key)
d1.pop('c')
print(d1)

# popitem() ==> to delete the last item from the dictionary
d1.popitem()
print(d1)

d1.popitem()
print(d1)

# clear() ==> remove all the items from the dictionary
d1.clear()
print(d1)

# del property ==> delete the dictionary permanently.
del d1

print(d1)


Assignment:
===========
1) WAP TO CREATE THE DYNAMICALLY DEFINED DICTIONARY AND FIND THE LENGTH OF THE DICTIONARY
i) WITHOUT BUILT-IN METHOD 
ii) WITH BUILT-IN METHOD ==> len()