How do I write a class to make this code work.
class number:
def double(self):
return n*2
print(number(44).double)
>> 88
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2 Answers
Well, you could decorate the number.double method with property:
class number:
def __init__(self, number):
self.number = number
@property
def double(self):
return self.number * 2
print(number(42).double) # 84
If you know the type of your argument, it'd be better to inherit number from it. For example
class number(int):
@property
def double(self):
return type(self)(self * 2)
print(number(42).double) # 84
print(number(42).double.double) # 168
3 Comments
L3viathan
Don't know why you're subclassing int when they're seem to be trying to write a generic numeric class.
vaultah
@L3viathan
number('Too generic huh?').doubleL3viathan
behaviour seems fine by me! If you don't want that, check for
int, float, long, and complex.Here you are:
class Number(object):
def __init__(self, n):
self.n = n
def double(self):
return 2*self.n
print(Number(44).double())
A couple of notes:
- Since
double()is a method of the classNumber(and not an attribute), you need to use parentheses to call it. - In Python it's considered standard practice to give classes uppercase names.
- If you want to define an instance variable (in this case
n, or44, you mustdefthe__init__()function which gives the interpreter instructions for how to create, or initialize an instance of your class.
Hope this helps, and good luck!
2 Comments
Nohl
I am making an exercise on codewars and I need to use the following syntaxe. I don't think I can use a method. Here is the test case. test.assert_equals(PrimeFactorizer(24).factor, {2: 3, 3: 1})
pzp
Do you have the code or documentation for
test.assert_equals(). I'm almost positive that test.assert_equals() takes the actual function as an argument (rather than the value returned by calling the function), so that it can call the function itself. If this is so, then PrimeFactorizer.factor() is really a method even though you don't use parentheses when using it that particular way.