tags: #python/documentation/dictionaries

Accessing a Key-Value Pair

1. Using the items() Method

d.items()

The items() method returns a view object. The view object contains the key-value pairs of the dictionary, as tuples in a list.

Example:

# Example dictionary
my_dict = {'name': 'John', 'age': 25, 'city': 'New York'}

# Using items() to create a list of tuples
items_list = list(my_dict.items())

# Displaying the output
print("List of items:", items_list)

[('name', 'John'), ('age', 25), ('city', 'New York')]

Accessing Values

1. Using the Index Operator

To access a value associated with a key, we can use the index operator:

d[key]

Example:

person = {
    'first_name': 'John',
    'last_name': 'Doe',
    'age': 25,
    'favorite_colors': ['blue', 'green'],
    'active': True
}
print(person['first_name'])
print(person['last_name'])

Output:
John
Doe

2. Using the values() Method

To access values in a dictionary, we can use the values() method:

d.values()

This returns a view object that displays a list of all the values in the dictionary. We can use a For Loop to store the values returned with values() in a list:

vals = []

for i in d.values():
	vals.append(i)

This iterates through the values of the dictionary d and appends each value to the list vals.

Alternatively, we can store it in a list object directly:

list(d.values())

3. Using the items() Method

Similarly, we can get a list of values using the items() method:

vals = []

for key, value in d.items(): # Tuple unpacking/multiple assignment 
	vals.append(value)

4. Using the get() Method (Return value if not exists)

The get() method returns the value of the item associated with the specified key:

d.get(keyname, value)

• keyname (required): Associated key of the value which you want to retreieve.
• value (optional): A value to return if the specified key does not exist. Default value is None.

Example:

person = {
    'first_name': 'John',
    'last_name': 'Doe',
    'age': 25,
    'favorite_colors': ['blue', 'green'],
    'active': True
}

ssn = person.get('ssn')
print(ssn)

Output:
None

Accessing the Keys

1. Using the keys() Method

The keys() method returns a view object. The view object contains the keys of the dictionary, as a list.

d.keys()

To get a list of keys:

list(d.keys())

2. Using the items() Method

Similarly, we can get a list of keys using the items() method:

keys = []

for key, value in d.items(): # Tuple unpacking/multiple assignment 
	keys.append(key)