I'm confused in bellowing code:
class Point():
def __init__(self, x=0, y=0):
self.x = x
self.y = y
I do not understand what those two x in code self.x = x mean.
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possible duplicate of Python 'self' explaineduser2864740– user28647402015-01-17 22:58:37 +00:00Commented Jan 17, 2015 at 22:58
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4 Answers
self.x is an attribute of the Point class. So if p is an instance of the Point class, then p.x is the self.x you see above (self being a reference to the class you are defining). The second x is the parameter passed at init time def __init__(self, x=0, y=0):. Note that it defaults to zero in case you don't pass anything.
1 Comment
warvariuc
>
self.x is an attribute of the Point class< better: > self.x is an attribute of a Point class instance<The first x is an attribute of self, while the second comes into the method as its second argument.
You could write it as:
class Point():
def __init__(self, new_x=0, new_y=0):
self.x = new_x
self.y = new_y
and see which belongs to which one.
Comments
First read this question and answer: What is the purpose of self?. To your question, the first self.x is an attribute of self and the second x is an argument you are getting in your constructor for Point
3 Comments
stardiviner
I did a search before I ask, and I have seen that question and answer, I found I still can not solve my confuse. that's why I ask. Actually some of explains in that answers is difficult to understand for me. But that answers are good for me. thanks.
zenpoy
I didn't imply you didn't make any research, I just pointed out a good starting point for you to read, so that my answer would make sense without having to explain what
self is... cheers.stardiviner
My mistake, I should clarify that I have checkout those questions.
class Employee:
def __init__(self, name, salary):
self.name = name
self.salary = salary # self ? ? ?
def displayEmployee(self):
salary = -69
print self.name, self.salary,salary # self ? ? ?
run:
emp1 = Employee("nick", 2000)
emp1.displayEmployee() # self ! ! !
output:
nick 2000 -69
'self' explained! : self.salary = 2000 , salary = -69
3 Comments
Dan Oberlam
Mind adding even a little bit of explanation as to how this applies?
Dan Oberlam
Explain everything. It is unclear how it applies to the question, especially for a user who doesn't understand the topic well
nick k
This 'self' topic has been 'explained' by many others , so try some other explanation if you don't like mine.