How to fix the assertion error in this problem?

Question

I'm having a problem fixing the error below. I'm returning correct outputs, then the assertion error occurred. How to fix it? What should I do?

Example Usage:

from vector import Vector

v1 = Vector(1, 1, 0)   # Initialize vector <1,1,0>
v2 = Vector(2, 1, 3)   # Initialize vector <2,1,3>

print(v1)              # Should print "<1,1,0>"
print(v2)              # Should print "<2,1,3>"

v3 = v1 + v2 
print (v3)             # v3 is <3,2,3>
v4 = v1 * 3  
print (v4)             # v4 is <3,3,0>
v5 = v2 * 2 
print(v5)              # v5 is <4,2,6>


c_p = v1.cross_product(v2) 
print(c_p)            # returns <3,-3,-1>
d_p = v1.dot_product(v2) 
print(d_p)            # returns 3
m = v1.magnitude()    # returns 1.4142135623730951
print (m)

---

This is my code:

import math
class Vector:
  def __init__(self, x=0, y=0, z=0):
    self.x = x
    self.y = y
    self.z = z

  def __str__(self):
    return '<{}, {}, {}>'.format(self.x,self.y,self.z)

  def __add__(self, other):
    return Vector(self.x+other.x,self.y+other.y,self.z+other.z)

  def __mul__(self, other=int()):
    return Vector(self.x*other,self.y*other,self.z*other)

  def cross_product(self, other):
    c = (self.y*other.z - self.z*other.y,self.z*other.x- self.x*other.z,self.x*other.y - self.y*other.x)
return c

  def dot_product(self, other):
    d = (self.x*other.x + self.y*other.y + self.z*other.z)
    return d

  def magnitude (self):
    e = (math.sqrt(self.x**2 + self.y**2 + self.z**2))
    return e

---

Outputs from my code:

  <1, 1, 0>
  <2, 1, 3>
  <3, 2, 3>
  <3, 3, 0>
  <4, 2, 6>
  (3, -3, -1)
  3
  1.4142135623730951

---

The error, I am guessing that this could be due to whitespaces? I tried resolving it though.

, line 12, in test_vector
    self.assertEquals(str(v1), "<2,1,-2>")
AssertionError: '<2, 1, -2>' != '<2,1,-2>'
- <2, 1, -2>
?    -  -
+ <2,1,-2>

Answer 1

Just like this:

class Vector:
  def __init__(self, x=0, y=0, z=0):
    self.x = x
    self.y = y
    self.z = z

  def __str__(self):
    return '<{},{},{}>'.format(self.x,self.y,self.z)