What Is Dictionary In Python

• Dictionary is likely the most important built-in Python data structure.

• Dictionaries store a mapping between a set of keys and a set of values.

• Keys are variables, and they are listed together with the values assigned to them. This forms a key-value pair.

• The keys can be of any immutable type and the values can be of any type.

• A dictionary is a flexibly-sized collection of key-value pairs, where keys and values are Python objects.

How To Store Data In Dictionary In Python

dict1 = {'Name' : "Zara", "Age" : 7, "Class" : "First"}

dict1 

Output:

{'Name': 'Zara', 'Age': 7, 'Class': 'First'}

How to fetch the column names in Dictionary In Python

dict1.keys()

Output:

dict_keys(['Name', 'Age', 'Class'])

How To Fetch Values From Dictionary In Python

dict1.values()

Output:

dict_values(['Zara', 7, 'First'])

How To Fetch The Key Value Pair From Dictionary In Python

dict1.items()

Output:

dict_items([('Name', 'Zara'), ('Age', 7), ('Class', 'First')])

How To Access The Values In Dictionary In Python

The Python Dictionary object provides a key:value indexing facility.

Note that dictionaries are unordered - since the values in the dictionary are indexed by keys, they are not held in any particular order, unlike a list, where each item can be located by its position in the list.

How To Access The Values In Dictionary By the Keys

print (dict1['Name'])

print ()

print (dict1["Age"])

Output:

Zara

7

Here we have accessed the values by the keys like Name and Age

How To Update Dictionary

dict1 = {'Name': 'Zara', 'Age': 7, 'Class': 'First'}

print (dict1)

print ()

print (dict1['Age'])

print ()

dict1['Age'] = [7,8] # updating/ modifying a value

print (dict1)

print ()

dict1['School'] = 'DPS' # adding a key value pair

print (dict1)

Output:

{'Name': 'Zara', 'Age': 7, 'Class': 'First'}

7

{'Name': 'Zara', 'Age': [7, 8], 'Class': 'First'}

{'Name': 'Zara', 'Age': [7, 8], 'Class': 'First', 'School': 'DPS'}

How To Delete Key Value Pair In Dictionary In Python

print (dict1)

print ()

print (dict1["School"])

print ()

del dict1["School"]

print (dict1)

Output:

We have deleted School column and it's value from the dictionary

{'Name': 'Zara', 'Age': [7, 8], 'Class': 'First', 'School': 'DPS'}

DPS

{'Name': 'Zara', 'Age': [7, 8], 'Class': 'First'}

How to clear Dictionary

dict1.clear()

print (dict1) # empty the dictionary

Output:

{}

How To Delete Dictionary

del (dict1)

print (dict1)

Output:

It will throw error dictonary does not exist

How To Remove Item From Dictionary

thisdict = {

  "brand": "Ford",

  "model": "Mustang",

  "year": 1964

}

thisdict.pop("model")

print(thisdict)

Output:

{'brand': 'Ford', 'year': 1964}

How To Print Key Values In Dictionary Using For Loop In Python

thisdict = {

  "brand": "Ford",

  "model": "Mustang",

  "year": 1964

}

for x in thisdict:

  print(x)

Output:

brand

model

year

The keys() method also can be used to return the keys of a dictionary:

thisdict = {

  "brand": "Ford",

  "model": "Mustang",

  "year": 1964

}

for x in thisdict.keys():

  print(x)

Output:

brand

model

year

item() method can be used to fetch key value pair from the Dictionary

thisdict = {

  "brand": "Ford",

  "model": "Mustang",

  "year": 1964

}

for x, y in thisdict.items():

  print(x, y)

Output:

brand Ford

model Mustang

year 1964

How To Print Values In Dictionary Using For Loop In Python

thisdict = {

  "brand": "Ford",

  "model": "Mustang",

  "year": 1964

}

for x in thisdict:

  print(thisdict[x])

Output:

Ford

Mustang

1964

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

thisdict = {

  "brand": "Ford",

  "model": "Mustang",

  "year": 1964

}

for x in thisdict.values():

  print(x)

Output:

Ford

Mustang

1964