title: Python append 1 to list if condition exist and 0 to all other lists
body: <p>I have 3 lists:</p>
  
  <pre><code>a_exist = []
  b_exist = []
  c_exist = []
  </code></pre>
  
  <p>i am looping through a main list of strings:</p>
  
  <pre><code>l = ['a', 'b']
  
  for item in l:
  
      if 'a' in item:
  
          a_exist.append(1)
          b_exist.append(0)
          c_exist.append(0)
  
      else:
  
          a_exist.append(0)
          b_exist.append(0)
          c_exist.append(0)
  
      if 'b' in item:
  
          b_exist.append(1)
          a_exist.append(0)
          c_exist.append(0)
  
      else:
  
          b_exist.append(0)
          a_exist.append(0)
          c_exist.append(0)
  </code></pre>
  
  <p>What i am trying to get:</p>
  
  <pre><code>a_exist = [1,0]
  b_exist = [0,1]
  c_exist = [0,0]
  </code></pre>
  
  <p>Is there a better way of doing this?</p>