Python dictionary is an unordered collection of elements that are changeable and indexed. Dictionaries are written with curly braces, and they have keys and values. While other compound data types like lists or tuples have only value as an item, a dictionary has a key-value pair.
How to create a dictionary in Python
To create a dictionary in Python, place elements inside curly braces {} separated by a comma. An element has a key; the corresponding value is expressed as a key-value pair.
dictA = {'name': 'Krunal', 'age': 26}
print(dictA)
Output
The above is the simplest way to create a dictionary.
In Dictionary, the values can be of any data type and can repeat, but the keys must be immutable and unique. Therefore, dictionaries must have unique keys.
We can also use the dict() method to create a dictionary.
dictB = dict({1:'Django', 2:'Flask'})
print(dictB)Output
How to access elements in Dictionary
To access elements in the Python dictionary, refer to their key name inside square brackets.
dictB = dict({1:'Django', 2:'Flask'})
print(dictB[1])Output
You can also use the get () method, which will give you the same result.
dictB = dict({1:'Django', 2:'Flask'})
print(dictB.get(1))How to modify in Dictionary in Python
To change a dictionary in Python, use an assignment operator.
A dictionary is mutable; that is why we can add new items or change the value of an existing object. In addition, you can change the value of the specific element by referring to its key name.
The value gets updated if the key is present; a new key: value pair is added to the Dictionary.
dictC = {'phpf1': 'Laravel', 'phpf2':'Symfony', 'phpf3':'Zend'}
print(dictC)
dictC['phpf3'] = 'Yii'
print('After changing values: ')
print(dictC)Output
Add the item to the Dictionary.
dictC = {'phpf1': 'Laravel', 'phpf2':'Symfony', 'phpf3':'Zend'}
print(dictC)
dictC['phpf4'] = 'Yii'
print('After adding values: ')
print(dictC)Output
How to remove an element from a dictionary
To remove an element from a dictionary in Python, you can use the “dict.pop()” method. The pop() method removes an item with the provided key and returns the value.
dictD = {1:18, 2:19, 3:20, 4:21}
poppedE = dictD.pop(3)
print('Popped Item: ',poppedE)
print(dictD)Output
How to loop through a Dictionary in Python
To loop through a dictionary in Python, use the for loop. The for loop is used to iterate each element of the Dictionary. When looping through the Dictionary, the return value is the key to the Dictionary, but we can also return the values.
dictK = {'c1': 'Ben 10', 'c2': 'Kung Fu Panda', 'c3': 'Scooby Doo'}
for key in dictK:
print(dictK[key])
Output
We can also print the keys.
dictK = {'c1': 'Ben 10', 'c2': 'Kung Fu Panda', 'c3': 'Scooby Doo'}
for key in dictK:
print(key)Dictionary methods
| Method | Description |
| dict.clear() | It removes all the elements from the dictionary |
| dict.copy() | It returns a copy of the dictionary |
| dict.get() | It returns the value of specified key |
| dict.items() | It returns a list containing a tuple for each key-value pair |
| dict.keys() | It returns a list containing the dictionary’s keys |
| dict.update() | It updates the dictionary with specified key-value pairs |
| dict.values() | It returns a list of all the values of the dictionary |
| dict.pop() | It remove the element with the specified key |
| dict.popItem() | It removes the last inserted key-value pair |
| dict.setdefault() | It sets the key to the default value if the key is not specified in the dictionary |
That’s it.
Krunal Lathiya is a seasoned Computer Science expert with over eight years in the tech industry. He boasts deep knowledge in Data Science and Machine Learning. Versed in Python, JavaScript, PHP, R, and Golang. Skilled in frameworks like Angular and React and platforms such as Node.js. His expertise spans both front-end and back-end development. His proficiency in the Python language stands as a testament to his versatility and commitment to the craft.
