Python Tips - A little intro to Python Properties
Hi there ! Welcome in a new episode of Python Tips !
Today we are taking a look at the property decorator.
Classic getter an setter
If you are a Java developper and you just switched to Python, perhaps you are doing this:
class Employee(object):
def __init__(self, name, salary):
self._name = name
self._salary = salary
# Java-style getter/setter
def getName(self):
return self._name
def setName(self, name):
self._name = name
def getSalary(self):
return self._salary
def setSalary(self, salary):
self._salary = salary
If you do, you can go burn in hell !
But why ? It's working.
Because, define methods like this is not very Pythonic... Python provide a lot to not have to deal directly with setters an getters.
You can do this instead.
class Employee(object):
def __init__(self, name, salary):
self.__name = str()
self.__salary = float()
self.name = name
self.salary = salary
# Python-style getter/setter
@property
def name(self):
return self._name
@salary.setter
def salary(self, new_name):
if not type(new_name) in [str] or len(new_name) < 2:
raise TypeError
else:
self.__name = float(new_name)
@property
def salary(self):
return self._salary
@salary.setter
def salary(self, new_salary):
if new_salary < 0 or not type(new_salary) in [float,int]:
raise TypeError
else:
self.__salary = float(new_salary)
***Much better ! ***
Now you can do this !
>>>e = Employee('li', 1200.12)
>>>e.salary = -1
Traceback (most recent call last):
File "/home/slash/Documents/Programmation/projets/hive-base/content/series/PythonTips/PythonTips_n8-Properties/static/Employee.py", line 33, in <module>
e.salary = -1
File "/home/slash/Documents/Programmation/projets/hive-base/content/series/PythonTips/PythonTips_n8-Properties/static/Employee.py", line 26, in salary
raise TypeError
TypeError
>>> e.salary # haven't changed
1200.12
Awesome !
Now we know how to use properties in place of get and set methods !
More info on properties here
You made it to the end, bravo! If you have any questions, don't forget to ask. See you next time! If you spot a grammar or vocabulary mistake, please let me know in the comments.
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