Sum of items of a class
Question:
What I have to do is to create a class that counts from a giving single argument and itself make the arithmetical operation.
class Counts:
def __init__(self, value=0):
self.value = value
def newvalue(self, other):
return Counts(self.value + other)
But for every I make to the code I got any different error, either syntax or callable argument.
The idea is to get
Counts()
Expected output
0
Next
Counts.newvalue(10)
Expected output
10
Next
Counts.newvalue(40)
Expected output
50
Next
Counts.newvalue(-17)
Expected output
33
And so on.
Answers:
The code that shows the expected behaviour is
class Counts:
value = 0
def __new__(self):
return self.value
@classmethod
def newvalue(cls, other):
cls.value += other
return cls.value
however this is a somewhat strange piece of code, as you are creating a class that returns a value when initialized instead of an object deriving from that class by overriding __new__
, which is pretty non-standard.
also if you want to zero the value whenever Count()
is called, you can add a self.value = 0
before the return self.value
Tests ->
print(Counts())
print(Counts.newvalue(10))
print(Counts.newvalue(40))
print(Counts.newvalue(-17))
returns
0
10
50
33
What I have to do is to create a class that counts from a giving single argument and itself make the arithmetical operation.
class Counts:
def __init__(self, value=0):
self.value = value
def newvalue(self, other):
return Counts(self.value + other)
But for every I make to the code I got any different error, either syntax or callable argument.
The idea is to get
Counts()
Expected output
0
Next
Counts.newvalue(10)
Expected output
10
Next
Counts.newvalue(40)
Expected output
50
Next
Counts.newvalue(-17)
Expected output
33
And so on.
The code that shows the expected behaviour is
class Counts:
value = 0
def __new__(self):
return self.value
@classmethod
def newvalue(cls, other):
cls.value += other
return cls.value
however this is a somewhat strange piece of code, as you are creating a class that returns a value when initialized instead of an object deriving from that class by overriding __new__
, which is pretty non-standard.
also if you want to zero the value whenever Count()
is called, you can add a self.value = 0
before the return self.value
Tests ->
print(Counts())
print(Counts.newvalue(10))
print(Counts.newvalue(40))
print(Counts.newvalue(-17))
returns
0
10
50
33