title: My conditional variable on my if statement is being changed by the statement, even though it doesn't appear in the statement. Why?
body: <p>I want to create two matrices. Then make the second matrix numbers changed depending on the numbers in the first matrix. So I generate an If statement about my first matrix and if true this will induce a change in my second matrix. However, it induces a change in both matrices?</p>
  
  <p>My code works perfectly with single digit objects. It only occurs when I try to apply it with matrices.</p>
  
  <pre><code>import numpy as np
  n = 3
  matr = np.zeros((n,n))
  matr[0][0] = 1
  matr2 = matr
  
  print(matr)
  [[1. 0. 0.]
   [0. 0. 0.]
   [0. 0. 0.]]
  
  print(matr2)
  [[1. 0. 0.]
   [0. 0. 0.]
   [0. 0. 0.]]
  
  if matr[0][0] == 1:
      matr2[0][0] = 9
  
  print(matr)
  [[9. 0. 0.]
   [0. 0. 0.]
   [0. 0. 0.]]
  
  print(matr2)
  [[9. 0. 0.]
   [0. 0. 0.]
   [0. 0. 0.]]
  </code></pre>
  
  <p>Because "matr" doesn't occur as a subject in my if statement it shouldn't be altered right?</p>
  
  <pre><code>x = 1
  y = x
  
  if x == 1:
      y = 9
  
  print(x)
  1
  print(y)
  9
  </code></pre>