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'person1': {'name': 'Alice', 'age': 25, 'gender': 'female'},
'person2': {'name': 'Bob', 'age': 30, 'gender': 'male'}
}
In this example, myDict is a dictionary that contains two keys, 'person1' and 'person2'. The value for each of
these keys is another dictionary, which contains information about each person.
To access a value in a nested dictionary, we can use multiple square brackets to drill down to the desired level. For
example, to access the name of person1 in the above example, you can do:
name = myDict['person1']['name']
print(name)
Sample Output:
'Alice'
In this example, myDict['person1'] returns the inner dictionary for 'person1', and myDict['person1']
['name'] returns the value associated with the 'name' key in that inner dictionary.
8.4 Dictionary Methods
Python provides several methods for manipulating dictionaries. Unlike strings and tuples, a dictionary is a mutable
object. To invoke a method associated with a dictionary object, the dict object is followed by a dot, followed by the
name of the method, followed by a pair of parentheses that encloses the arguments (if any) required for invoking the
method. Using a dictionary object myDict, we describe some methods that apply to the dictionaries:
● myDict.keys(): The method keys() returns a dict_keys object comprising all the keys included in the
dictionary. We can iterate over the keys in the dict_keys object and also check for membership of a key.
However, dict_keys does not support indexing.
Example:
>>> subjects
{'Sanskrit': 78, 'English': 185, 'Maths': 88, 'Hindi': 90}
>>> subjects.keys()
dict_keys(['Sanskrit', 'English', 'Maths', 'Hindi'])
>>> 'English' in subjects.keys()
True
>>> for subject in subjects.keys():
... print(subject, end = ' ')
...
...
Sanskrit English Maths Hindi
>>> subjects.keys()[0]
Traceback (most recent call last):
File "<pyshell#38>", line 1, in <module>
subjects.keys()[0]
TypeError: 'dict_keys' object is not subscriptable
C T 01 Consider the dictionary, myDict.
>>> myDict = { 'b':'beta', 'g':'gamma', 'a':'alpha' }
Display all the keys of myDict.
● myDict.values(): The method values() returns a dict_values object comprising all the values included
in the dictionary. We can iterate over the values in the dict_values object and also check for membership of
a value in a dict_values. However, dict_values does not support indexing.
Python Dictionaries 197

