title: Python - finding complement of 2 lists
body: <p>I'm looking for a method that would allow me to check what elements are missing when comparing 2 lists. A lot like in this thread but I want to write this in NumPy Python.</p>
  
  <p><a href="https://stackoverflow.com/questions/5939404/complement-of-two-lists">Complement of Two Lists?</a></p>
  
  <pre><code>import numpy as np
  
  numbers = np.array([1,2,3,4,5,6,7,8,9])
  A = np.array([2,5,6,9])
  
  def listComplementElements(list1, list2):
  
      storeResults = []
  
      for i in list1:
          for j in list2:
  
              if i != j:
                  #write to storeResults if 2 numbers are different
                  storeResults.append(i)
              else:
                  #if numebrs are equal break out of the loop
                  break
  
      return storeResults            
  
  result = listComplementElements(numbers, A)
  print(result) #expected result [1,3,4,7,8]
  </code></pre>
  
  <p>At the moment the output looks like this: [1, 1, 1, 1, 3, 3, 3, 3, 4, 4, 4, 4, 5, 6, 6, 7, 7, 7, 7, 8, 8, 8, 8, 9, 9, 9] </p>
  
  <p>What am I doing wrong? </p>