Categories: python

Python Dictionary

Python Dictionary is used to store the data in a key-value pair format. Python’s dictionary data type can mimic real-world data arrangements where a particular value exists for a particular key. The mutable data structure is what it is. The element Keys and values is used to define the dictionary.

  • Keys must consist of just one thing.
  • Any type of value is acceptable, including list, tuple, integer, etc.

Example:

Dict = {1: 'Rahul', 2: 'Shruti', 3: 'Ron'}
print(Dict)

Output:

{1: 'Rahul', 2: 'Shruti', 3: 'Ron'}
Dictionary and List:

The following traits apply to both dictionaries and lists:

  • Both are mutable.
  • Both are dynamic. They can expand and contract as necessary.
  • Both can be nested. One list may include another list. Another dictionary may be found inside one. A list can also be found in a dictionary, and vice versa.

Lists and dictionaries differ primarily in the way that elements are accessed:

  • Indexing allows access to list elements based on their location within the list.
  • Keys are used to accessing dictionary elements.
Dictionary with integer keys:
Dict = {1: 'Rahul', 2: 'Shruti', 3: 'Ron'}
print(Dict)
Dictionary with String keys:
Dict = {'ab': 'Rahul', 'cd': 'Shruti', 'ef': 'Ron'}
print(Dict)
Empty Dictionary:
Dict = {}
print("Empty Dictionary: ")
print(Dict)

Output:

Empty Dictionary: 
{}
Nested Dictionary:

Dict = {1: 'Maths', 2: 'HIndi',
  3: {'S1': 'Biology', 'S2': 'Chemistry', 'S3': 'physics'}}

print(Dict)

Output:

{1: 'Maths', 2: 'HIndi', 3: {'S1': 'Biology', 'S2': 'Chemistry', 'S3': 'physics'}}
Accessing elements of a dictionary:
Dict = {'ab': 'Rahul', 'cd': 'Shruti', 'ef': 'Ron'}
print(Dict)
for i in Dict:
    print ("Key: " + i + " and Element: " + Dict[i]);

Output:

{'ab': 'Rahul', 'cd': 'Shruti', 'ef': 'Ron'}
Key: ab and Element: Rahul
Key: cd and Element: Shruti
Key: ef and Element: Ron
Deleting element(s) in a dictionary:

Deleting elements with the del keyword is similar to removing items from a list.

Example:


Dict = {1: 'Maths', 2: 'HIndi',
  3: {'S1': 'Biology', 'S2': 'Chemistry', 'S3': 'physics'}}
del Dict[3]
print(Dict)

Output:

{1: 'Maths', 2: 'HIndi'}

Note: also read about Remove elements from a Python List

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