Page 426 - Computer Science V2.0 Class 11

>>> months
{3: 'March', 12: 'December', 1: 'January'}
The Python keyword operator del can also be used to delete a dictionary entirely.
>>> del months #delete months
As expected, since the dictionary months has been deleted, accessing it leads to an error:
>>> months
Traceback (most recent call last):
File "<pyshell#17>", line 1, in <module>
months
NameError: name 'months' is not defined. Did you mean: 'months'?
● myDict.clear(): The method clear() removes all key-value pairs from the dictionary. However, the
dictionary object itself is not deleted.
Example:

>>> months = {3:'March', 11:'November', 12: 'December', 1:'January'}
>>> months.clear()
>>> months
{}
● myDict.get(myKey, val): The method get() returns the value of the item with the specified key (myKey),
just like myDict[myKey], If there is a key-value pair with the specified key (myKey), Python ignores the second
argument (if provided). However, if there is no key-value pair with the specified key (myKey), Python returns the
second argument, if provided, and None otherwise.

Example:
>>> myDict = { 'b':'beta', 'g':'gamma', 'a':'alpha' }
>>> myDict.get('g')
'gamma'
>>> myDict['g']
'gamma'
>>> print(myDict.get('d'))
None
>>> myDict.get('d', -1)
-1
● myDict.copy(): copy() method returns the copy of the dictionary.

Example:
>>> myDict = { 'b':'beta', 'g':'gamma', 'a':'alpha' }
>>> myDictCopy = myDict.copy()
>>> myDictCopy
{'b': 'beta', 'g': 'gamma', 'a': 'alpha'}
>>> id(myDict), id(myDictCopy)
(2386829086208, 2386829094976)
Note that the variables myDict and myDictCopy refer to two different objects having the ids 2386829086208
and 2386829094976, respectively.
● myDict.fromkeys(<keys>, <value>): The method fromkeys() returns a dictionary with the specified
keys and the specified value. Interestingly, the method does not update the existing dictionary myDict.
Example:
>>> subjects = {}
>>> subjectTitle = {'Physics', 'Mathematics', 'Computer Sc.'}
>>> marks = 0
>>> subjects.fromkeys(subjectTitle, marks)
{'Computer Sc.': 0, 'Mathematics': 0, 'Physics': 0}
>>> subjects
{}

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