What is Dictionary in Python with examples?

Dictionary

A dictionary is a mixed collection of elements. Unlike other collection data types such as a list or tuple, the dictionary type stores a key along with its element. It also a mutable data type.

.The keys in a Python dictionary are separated by a colon ( : ) while the commas work as a separator for the elements. The key-value pairs are enclosed with curly braces { }.

Syntax of Dictionary:

Dict_Name = {key_1:val_1, key_2:val_2,key_3:val_3}

Accessing values in the dictionary

To access values in dictionary, square brackets are used along with the key to get values

Example 1: #single values

• >>>Dict = {‘name’:’Iterathon’, ‘subject’:’Blog’}
• >>>print(Dict[name])
  • Iterathon
• >>>print(Dict[subject])
  • Blog

Example 2: #All values

• >>>Dict = {‘name’:’Iterathon’, ‘subject’:’Blog’}
• >>>print(Dict.values())
  • dict_values([‘Iterathon’, ‘blog’])

Accessing keys in the dictionary

To access keys in dictionary, use one magical word called keys().

Example:

• >>>Dict = {‘name’:’Iterathon’, ‘subject’:’Blog’}
• >>>print(Dict.keys())
  • dict_keys([‘name’, ‘subject’])

Some important operations in python

• len()
• clear()
• copy()
• items ()
• keys()
• values()
• get()
• setdefault()
• del

len()

len() returns the length of the dictionary that is total pairs (keys and values)

Example:

• >>>Dict = {‘name’:’Iterathon’, ‘subject’:’Blog’}
• >>>print(len(Dict)
  • 2

clear()

clear() is used to delete all elements in the dictionary. it returns a empty dictionary.

Example:

• >>>Dict = {‘name’:’Iterathon’, ‘subject’:’Blog’}
• >>>print(Dict.clear())
  • None
• >>>print(Dict)
  • {}

copy()

copy() returns a original duplicate of the dictionary.

Example:

• >>>Dict = {‘name’:’Iterathon’, ‘subject’:’Blog’}
• >>>dict = (Dict.copy())
• >>>print(dict)
  • {‘name’:’Iterathon’, ‘subject’:’Blog’}

items()

items() returns whole dictionary that is both key and value pairs.

Example:

• >>>Dict = {‘name’:’Iterathon’, ‘subject’:’Blog’}
• >>>print(Dict.items())
  • dict_items([(‘name’, ‘Iterathon’), (‘subject’, ‘Blog’)])

keys()

keys() is used to returns a keys in the dictionary.

Example:

• >>>Dict = {‘name’:’Iterathon’, ‘subject’:’Blog’}
• >>>print(Dict.keys())
  • dict_keys([‘name’, ‘subject’])

values()

values() is used to returns the values in the dictionary.

Example:

• >>>Dict = {‘name’:’Iterathon’, ‘subject’:’Blog’}
• >>>print(Dict.values())
  • dict_values([‘Iterathon’, ‘Blog’])

get()

get() returns the value for the key passed as arguments. If the key is not present, It returns None.

Example:

• >>>Dict = {‘name’:’Iterathon’, ‘subject’:’Blog’}
• >>>print(Dict.get(‘name’))
  • Iterathon
• >>>print(Dict.get(‘Iterathon’))
  • None

setdefault()

setdefault() is used to sets a default value for keys that not present in the dictionary.

Example:

• >>>Dict = {‘name’:’Iterathon’, ‘subject’:’Blog’}
• >>>dict = Dict.setdefault(“motive”,”Learn Python Easy”)
• >>>print(dict)
  • Learn Python Easy

del

del is used to deletes a entire dictionary including spaces. After deletion, you tried to call that the dictionary, It led to thrown an error.

Example:

• >>>Dict = {‘name’:’Iterathon’, ‘subject’:’Blog’}
• >>>del Dict
• >>>print(Dict)
  • NameError: name ‘a’ is not defined

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