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Python Object-Oriented Python Advanced Objects Multiplication

Posted by Siddhartha Kala
Siddhartha Kala
4,170 Points

What is wrong with __rmul__

What am i doing wrong with rmul. I keep getting error that says cannot multiply number to NumString

numstring.py 
class NumString:
    def __init__(self, value):
        self.value = str(value)

    def __str__(self):
         return self.value

    def __int__(self):
        return int(self.value)

    def __float__(self):
        return float(self.value)

    def __add__(self, other):
        if '.' in self.value:
            return float(self) + other
        return int(self) + other

    def __radd__(self, other):
        return self + other

    def __iadd__(self, other):
        self.value = self + other
        return self.value

    def __mul__(self, other):
        if '.' in self.value:
            return float(self) * float(other)
        else: 
            return int(self) * int(other) 

    def __rmul__(self, other):
        if '.' in self.value:
            return float(self) * float(other)
        else: 
            return int(self) * int(other)

1 Answer

Steven Parker
Steven Parker
231,269 Points
Steven Parker
Steven Parker
231,269 Points

Try using the existing __add__ and __radd__ methods as models, and just changing the math operator.

Siddhartha Kala
Siddhartha Kala
4,170 Points

Thats the first thing I tried, but, keep getting the following error message:

 Bummer! Can't multiply a number with a `NumString` (i.e. `10 * NumString`)

Here is what i tried:

def rmul(self, other): return self * other

Steven Parker
Steven Parker
231,269 Points
Steven Parker
Steven Parker
231,269 Points

That looks good, now what about __mul__?

Siddhartha Kala
Siddhartha Kala
4,170 Points

I got it now. Thanks a lot. Had to remove float and int from other in mul