Dictionaries

'''
Dictionaries in Python:
In Python, dictionary is a built-in data type that stores data as key-value pairs.
They stores multiple items in a single variable.
They are separated by commas and enclosed within curly brackets{}.
They are ordered collection of data items.

Key Characteristics:
1. Ordered: Items do not have a defined order in Python versions < 3.7. In Python 3.7+, they maintain insertion order.
2. Mutable: We can change, add, or remove items.
3. Indexed by Keys: Each value is accessed using a unique key.
4. Keys Must Be Unique: Duplicate keys are not allowed.

Syntax:
dictionary_name = {
    "key1": "value1",
    "key2": "value2",
    "key3": "value3"
}
'''

#Example:
dic = {
    "Sindhu": "Human Being",
    "Lion"  : "Animal",
    "Parrot": "Bird"
}
print(dic["Sindhu"])             #output = Human Being
print(dic["Lion"])               #output = Animal
print(dic["Parrot"])             #output = Bird 

info = {"Name": "Sindhu", "Age": 23, "Eligible": True}
print(info)                     #output = {'Name': 'Sindhu', 'Age': 23, 'Eligible': True}

'''
Accessing Dictionary Items:
1. Accessing Single Values:
Values in a dictionary can be accessed useing keys.
We can access dictionary values by mentioning keys either in square brackets or or by using get method.

2. Accessing Multiple Values:
We can print all the values in the dictionary by using values method().
'''
#Example1:
info = {"Name": "Sindhu", "Age": 23, "Eligible": True}
print(info)                     #output = {'Name': 'Sindhu', 'Age': 23, 'Eligible': True}
print(info["Name"])             #output = Sindhu
print(info.get("Name"))         #output = Sindhu
#print(info["Name2"])           #output = KeyError: 'Name2'
#print(info.get("Name2"))        #output = None

info = {"Name": "Sindhu", "Age": 23, "Eligible": True}
print(info.values())            #output = dict_values(['Sindhu'], 23, True)
print(info.keys())              #output = dict_keys(['Name', 'Age', 'Eligible'])

for key in info.keys():
    print(info[key])
# #output = Sindhu
#           23
#           True

for key in info.keys():
    print(f"The value corresponding to the key {key} is {info[key]}")
# output = The value corresponding to the key Name is Sindhu
#          The value corresponding to the key Age is 23
#          The value corresponding to the key Eligible is True

'''
Accessing Keys:
We can access all the keys in the dictionary by using key() method.
'''
info = {"Name": "Sindhu", "Age": 23, "Eligible": True}
print(info.keys())              #output = dict_keys(['Name', 'Age', 'Eligible'])

'''
Accessing Key-Value Pairs:
We can print all the key-value pairs in the dictionary using items() method.
'''
info = {"Name": "Sindhu", "Age": 23, "Eligible": True}
print(info.items())            #output = dict_items([('Name' , 'Sindhu'),('Age' , 23), ('Eligible' , True)])

for key, value in info.items():
    print(f"The value corresponding to the key {key} is {value}")
#output = The value corresponding to the key Name is Sindhu
#         The value corresponding to the key Age is 23
#         The value corresponding to the key Eligible is True


 

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