Dictionary

#----------------Dictionary---------------#

#A dictionary is a collection which is unordered, changeable and indexed. In Python

dictionaries are written with curly brackets, and they have keys and values.

thisdict = {

'name': 'kamran',

'age': 24,

'Qualification': 'Btech'

}

print(thisdict)

#Output - {'name': 'kamran', 'age': 24, 'Qualification': 'Btech'}

#----------------->Accessing Items<------------------

#if you want to accessing only the name from the dictionary so you can use the Bracket

print(thisdict['name'])

#Output - kamran

#you can also use GET method for accessing the specific details from the dictionary

print(thisdict.get('name'))

#Output - kamran

#-------------------CHANGE VALUE-----------------

#You can change the value of a specific item by referring to its key name:

thisdict = {

'name': 'kamran',

'age': 24,

'date': 1995

}

thisdict['age'] = 23

print(thisdict)

#-----------------Loop Through a Dictionary---------------

#You can loop through a dictionary by using a for loop.When looping through a dictionary,

the return value are the keys of the dictionary, but there are methods to return the values as well.

#Print all key names in the dictionary, one by one:

for i in thisdict:

print(i)

#output - name

age

Qualification

#Print all values in the dictionary, one by one:

for i in thisdict:

print(thisdict[i])

#Output - kamran

24

Btech

#You can also use the values() function to return values of a dictionary:

for i in thisdict.values():

print(i)

#Output- kamran

24

Btech

#Loop through both keys and values, by using the items() function:

for i,j in thisdict.items():

print(i,j)

#Output - name kamran

age 24

Qualification Btech

#-------------------Check if Key Exists------------------

#Check if 'model' exist in dictionary:

thisdict = {

'brand': 'ford',

'model': 'khan',

'year': 2016

}

if 'model' in thisdict:

print('yes model is one of the key in the thisdict dictionary')

else:

print('model is not key of thisdict')

#Output - yes model is one of the key in the thisdict dictionary

#-------------Dictionary Length----------------------

print(len(thisdict))

#Output - 3

#-----------------ADD Items---------------------

#Adding an item to the dictionary is done by using a new index key and assigning a value to it:

thisdict['color'] = 'red'

print(thisdict)

#Output - {'brand': 'ford', 'model': 'khan', 'year': 2016, 'color': 'red'}

#-------------------Removing Items-------------------

#There are several methods to remove items from a dictionary:

thisdict.pop('model')

print(thisdict)

#The popitem() method removes the last inserted item

(in versions before 3.7, a random item is removed instead):

thisdict.popitem()

print(thisdict)

#Output - {'brand': 'ford', 'model': 'khan'}

#The del keyword removes the item with the specified key name:

del thisdict['model']

print(thisdict)

#Output - {'brand': 'ford', 'year': 2016}

#-----------------------Clear method--------------------

#The clear() keyword empties the dictionary:

thisdict.clear()

print(thisdict)

#-------------------Copy method------------------

#You cannot copy a dictionary simply by typing dict2 = dict1, because: dict2 will only be

a reference to dict1, and changes made in dict1 will automatically also be made in dict2.

#There are ways to make a copy, one way is to use the built-in Dictionary method copy().

#Make a copy of a dictionary with the copy() method:

mydict = thisdict.copy()

print(mydict)

#Another way to make a copy is to use the built-in method dict().

mydict = dict(thisdict)

print(mydict)

#Output - {'brand': 'ford', 'model': 'khan', 'year': 2016}

#---------------------Nested Dictionaries-----------------------

#A dictionary can also contain many dictionaries, this is called nested dictionaries.

#Create a dictionary that contain three dictionaries

myFamily = {

'child1':{'name': 'kamran','age': 24},

'child2':{'name':'aisha','age': 23},

'child3':{'name': 'ruhi','age': 26}

}

print(myFamily)

#-----------------------The dict() Constructor-----------------------

#It is also possible to use the dict() constructor to make a new dictionary:

thisdi = dict(brand = 'ford',model = 'khan',year = 2016)

print(thisdi)

#Output - {'brand': 'ford', 'model': 'khan', 'year': 2016}

#----------------------Update method--------------------------

car = {

'brand': 'ford',

'model': 'Mustang',

'year': 1964

}

car.update({'color': 'White'})

print(car)