Issue with def norm in class Vector

[DimosG]

Hi guys I am trying to calculate the norm(magnitude) of a Vector using class and when i run the code I get:

Error:
return math.sqrt(sum( i**2 for i in self ))
TypeError: 'Vector' object is not iterable

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44

import math   x = 2. y = 8. z = 6.     class Vector(object):     def __init__(self, data):         self.data = data         self.rows = len(data)           def __mul__(self, other):         assert len(self.data) == len(other.data)         result = 0.         for vi, vj in zip(self.data, other.data):             result += vi * vj         return result       def __rmul__(self, a):         data = [a * d for d in self.data]         return Vector(data)       def __add__(self, other):         assert len(self.data) == len(other.data)         data = [i + j for (i, j) in zip(self.data, other.data)]         return Vector(data)           def norm(self):         return math.sqrt(sum( i**2 for i in self ))               def __sub__(self, other):         assert len(self.data) == len(other.data)         data = [i - j for (i, j) in zip(self.data, other.data)]         return Vector(data)           def __str__(self):         return '{0}'.format(self.data)   I = Vector([1., 1., 1.]) v = Vector([1. + x, 2. + y, 3. + z]) w = Vector([4. + x, 5. + y, 6. + z]) Final = ( 2 * v - w ) + w.norm() * I print(Final.data)

[buran]

maybe you mean self.data?

[stullis]

Presumably, you want to iterate over the data attribute.

1 2	def norm(self):     return math.sqrt(sum( i**2 for i in self.data ))

[buran]

As a side note - you have Vector.rows but never use it. Instead you continue to use len(self.data) and len(other.data)

You may want to use @property

1 2 3

@property def rows(self):     return len(self.data)

then

1	assert self.rows == other.rows

and you are certain that self.rows will always yield the correct len

[DimosG]

Wow guys thanks a lot I am new to python and classes seem a bit strange to understand !