Questions tagged [class-attributes]
170 questions
3
votes
1 answer
Why class level attributes work with Null
I would think the following would throw NullPointerException
class N {
static int i;
public static void main( String ... args ) {
System.out.println( ((N)null).i );
}
}
But it doesn't. Why?
OscarRyz
- 196,001
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3
votes
1 answer
how to move function to class? python
I would like to to use service functions in a classmethod, where the service function is defined somewhere else. I want to be dynamic, so I can define different functions in different situations. I've tried this:
def print_a():
print 'a'
class…
Yaniv Haddad
- 49
- 4
3
votes
2 answers
Python design - initializing, setting, and getting class attributes
I have a class in which a method first needs to verify that an attribute is present and otherwise call a function to compute it. Then, ensuring that the attribute is not None, it performs some operations with it. I can see two slightly different…
Pietro Marchesi
- 852
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3
votes
2 answers
Lifetime of Python class attribute
What's the lifetime of a class attribute, in Python? If no instances of the class are currently live, might the class and its class attributes be garbage-collected, and then created anew when the class is next used?
For example, consider something…
D.W.
- 3,382
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3
votes
1 answer
Inheritable attributes in ruby classes
Greets to all!
I want to describe each kind of product by a class:
# Base product class
class BaseProduct
prop :name, :price # Common properties for all inheritable products
end
class Cellphone < BaseProduct
prop :imei # Concrete property for…
rbnoob
- 99
- 1
- 8
3
votes
2 answers
Python - Referencing class name from inside class body
In Python, I want to have a class attribute, a dictionary, with initialized values. I wrote this code:
class MetaDataElement:
(MD_INVALID, MD_CATEGORY, MD_TAG) = range(3)
mapInitiator2Type = {'!':MetaDataElement.MD_CATEGORY,
…
redism
- 500
- 7
- 18
3
votes
2 answers
Python shorthand for a tuple of a set of class attributes
Say i am using a class from some python package that looks like the following
class foo(object):
def __init__(self):
self.a = None
self.b = None
self.c = None
self.d = None
self.e = None
self.f =…
wich
- 16,709
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2
votes
3 answers
why superclass attributes are not available in the current class' namespace?
Example:
class A:
a = 1
class B(A):
b = 2
y = b # works fine
x = a # NameError: name 'a' is not defined
x = A.a # works fine
z = B()
z.a # works fine
B.a # works fine
Why is x = a not allowed? In every other context (access…
max
- 49,282
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- 355
2
votes
4 answers
When does Python fall back onto class __dict__ from instance __dict__?
Please see the below snippet:
class Foo:
class_var = "hi"
foo = Foo()
assert foo.class_var is Foo.class_var
assert "class_var" in Foo.__dict__
assert "class_var" not in foo.__dict__
All assertions here pass, though I am not sure if it's…
Intrastellar Explorer
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2
votes
2 answers
How to show that which class's variables are used in which class's operation(s) using UML diagram?
There is a class diagram that contains one class and this class has three operations (Oper1, Oper2, and Oper3) and three attributes (Attr1, Attr2, Atrr3). Now suppose:
1- Oper1 uses Attr1 and Attr2 to read from and write to them,
2- Oper2 uses Attr3…
Anmk
- 193
- 1
- 9
2
votes
2 answers
Redirecting function definitions in python
This is a very contrived example as it's not easy to explain the context in which I have ended up implementing this solution. However, if anyone can answer why this particular peculiarity happens, I'd be grateful.
The example:
class A(dict):
…
Dan
- 33,953
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2
votes
4 answers
How can i add atrributes to the class method from outside class?
This is gonna be my first question on this website. If I do mistake about English, sorry.
Okey, my question is how can I add or set attribute to the class method from outside class?
If i am not wrong,we use settatr() to do this. Can you guys help me…
Berke Balcı
- 81
- 10
2
votes
1 answer
Access class level attribute of another class?
I can access class-level attribute of a class (B) in method of another class (A) but I cannot access that at class-level of class A.
The issue can be resolved by defining B after A but why is this so and how can I access that keeping class B after…
ahsan naeem
- 245
- 2
- 9
2
votes
1 answer
how to easily find a class instance in a list with a given class attribute?
I'm a newbie. I am wondering if there is a way to easily find an instance of a class in a list with a given attribute. (Python)
basically the set up is as follows:
class idk:
def __init__(self, name, num):
self.name = name
…
IpsumPanEst
- 21
- 1
2
votes
2 answers
Python using class attributes with super when inheriting
I have a piece of python code:
class A(object):
args = [1,2]
def __init__(self):
print self.args
class B(A):
args = [3,4]
def __init__(self):
super(B, self).__init__()
print self.args
B()
The output is:
[3,…
jerrypeng
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