Lesson 7
Objects and Dictionaries
Chapter 4: Dictionaries
More dictionary methods
We have explored the following dict methods so far:
.get().keys().values().items()
There are several more dict methods listed in the official documentation.
Some of these are similar to list methods (.clear(), .pop()) so we will not discuss these, but feel free to play around with these yourself.
Here are two more methods that are specific to dict.
update()
The .update() method is like list’s .extend(), where you can concatenate another dict, or a list of 2-tuples to the existing dict.
>>> student_dict = {"00-01-30": "Ali", "00-02-11": "Simon",
... "00-05-67": "Francesca", "00-09-88": "Cho"
... }
...
>>> student_dict.update({"00-03-55": "Jose", "00-07-21": "Debora"})
>>> print(student_dict)
{'00-01-30': 'Ali', '00-02-11': 'Simon', '00-05-67': 'Francesca',
'00-09-88': 'Cho', '00-03-55': 'Jose', '00-07-21': 'Debora'}
>>> student_dict.update([("00-04-01", "Christina"), ("00-06-34", "Gerwazy")])
>>> print(student_dict)
{'00-01-30': 'Ali', '00-02-11': 'Simon', '00-05-67': 'Francesca',
'00-09-88': 'Cho', '00-03-55': 'Jose', '00-07-21': 'Debora',
'00-04-01': 'Christina', '00-06-34': 'Gerwazy'}
setdefault()
The .setdefault() method is similar to the .get() method. The main difference is that .setdefault() also adds the new key with a default value to the dict if the key does not exist.
>>> student_dict = {"00-01-30": "Ali", "00-02-11": "Simon",
... "00-05-67": "Francesca", "00-09-88": "Cho"
... }
...
>>> existing_student = student_dict.setdefault("00-09-88", "John Doe")
>>> print(existing_student)
Cho
>>> print(student_dict)
{'00-01-30': 'Ali', '00-02-11': 'Simon', '00-05-67': 'Francesca', '00-09-88': 'Cho'}
>>> new_unknown_student = student_dict.setdefault("11-22-33", "John Doe")
>>> print(new_unknown_student)
John Doe
>>> print(student_dict)
{'00-01-30': 'Ali', '00-02-11': 'Simon', '00-05-67': 'Francesca', '00-09-88': 'Cho',
'11-22-33': 'John Doe'}