Dictionary in Python

A Python dictionary is a collection of key-value pairs where each key is associated with a value. dictionary are used to store multiple items in a single variable. To separate two items, you use a comma ( , ) . A dictionary is like a list except that it uses parentheses { key : value } .

They are Immutable
A set doesn’t allow duplicate elements
The key cannot be changed

This program demonstrates the usage of dictionaries in Python. A dictionary is a collection of key-value pairs, where each key is unique. Initially, a dictionary 'user' is created with key-value pairs of user's name, age, and marital status.

The print statements show the dictionary, its type and the values corresponding to the keys "name" and "age".
The keys() method returns the keys of the dictionary, and the values() method returns the values of the dictionary.
The items() method returns a view of the dictionary's key-value pairs.
For loops are used to iterate over the keys, values and items of the dictionary and print them.
The in keyword is used to check if the "gender" key is present in the dictionary.
The dictionary values can be updated using the update() method and the [] operator.
The pop() method is used to remove the key-value pair with the given key, and the clear() method is used to remove all key-value pairs from the dictionary.

Another dictionary 'users' is created that contains two dictionaries - 'user1' and 'user2' - as its values.

The for loop is used to iterate over the keys of the dictionary, 'users', and print the values of the key "name" of each dictionary 'user1' and 'user2'.

Source Code

user = {
    "name": "Ram",
    "age": 25,
    "isMarried": True
}
print(user)
print(type(user))
print(user["name"])
print(user.get('age'))
print(user.keys())
print(user.values())
print(user.items())
for x in user:
    print(x," ",user[x])
for x in user.values():
    print(x)
for x in user.keys():
    print(x)
for x,y in user.items():
    print(x,y)
if "gender" in user:
    print("Present")
# Changing Values
user.update({"gender":"male"})
print(user)
user["age"]=35
print(user)
user.pop("age")
print(user)
user.clear()
print(user)
users={
    "user1": {
        "name": "Ram",
        "age": 25,
        "isMarried": True
    },
"user2": {
        "name": "SAm",
        "age": 35,
        "isMarried": False
    }
}
print(users)
for user in users:
    print(user["name"])

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Output

{'name': 'Ram', 'age': 25, 'isMarried': True}
<class 'dict'>
Ram
25
dict_keys(['name', 'age', 'isMarried'])
dict_values(['Ram', 25, True])
dict_items([('name', 'Ram'), ('age', 25), ('isMarried', True)])
name   Ram
age   25
isMarried   True
Ram
25
True
name
age
isMarried
name Ram
age 25
isMarried True
{'name': 'Ram', 'age': 25, 'isMarried': True, 'gender': 'male'}
{'name': 'Ram', 'age': 35, 'isMarried': True, 'gender': 'male'}
{'name': 'Ram', 'isMarried': True, 'gender': 'male'}
{}
{'user1': {'name': 'Ram', 'age': 25, 'isMarried': True}, 'user2': {'name': 'SAm', 'age': 35, 'isMarried': False}}