Python Dictionaries

Dictionaries are ordered collection of data items. They store multiple items in a single variable. Dictionary items are key-value pairs that are separated by commas and enclosed within curly brackets {}.

Example:

info = {'name':'Karan', 'age':19, 'eligible':True}
print(info)

Output:

{'name': 'Karan', 'age': 19, 'eligible': True}

Accessing Dictionary items:

I. Accessing single values:

Values in a dictionary can be accessed using keys. We can access dictionary values by mentioning keys either in square brackets or by using get method.

Example:

info = {'name':'Karan', 'age':19, 'eligible':True}
print(info['name'])
print(info.get('eligible'))

Output:

Karan
True

II. Accessing multiple values:

We can print all the values in the dictionary using values() method.

Example:

info = {'name':'Karan', 'age':19, 'eligible':True}
print(info.values())

Output:

dict_values(['Karan', 19, True])

III. Accessing keys:

We can print all the keys in the dictionary using keys() method.

Example:

info = {'name':'Karan', 'age':19, 'eligible':True}
print(info.keys())

Output:

dict_keys(['name', 'age', 'eligible'])

IV. Accessing key-value pairs:

We can print all the key-value pairs in the dictionary using items() method.

Example:

info = {'name':'Karan', 'age':19, 'eligible':True}
print(info.items())

Output:

dict_items([('name', 'Karan'), ('age', 19), ('eligible', True)])

Practice

info = {'name':'Karan', 'age':19, 'eligible':True}
# print(info) 
# print(info.keys())
# print(info.values())

# for key in info.keys():
#   print(f"The value corresponding to the key {key} is {info[key]}")

print(info.items())
for key, value in info.items():
  print(f"The value corresponding to the key {key} is {value}") 

Output:

dict_items([('name', 'Karan'), ('age', 19), ('eligible', True)])

The value corresponding to the key name is Karan
The value corresponding to the key age is 19
The value corresponding to the key eligible is True

Explanation:

• info = {'name':'Karan', 'age':19, 'eligible':True}

  • Creates a dictionary with key–value pairs.

• print(info.items())

  • Returns all key-value pairs as dictionary view objects.

  • Output format:

    dict_items([('name', 'Karan'), ('age', 19), ('eligible', True)])
    

• for key, value in info.items():

  • Loops through each key-value pair in the dictionary.

• print(f"The value corresponding to the key {key} is {value}")

  • Prints each key with its corresponding value.