title: TypeError: list indices must be integers or slices, not str 'convert the chararter'
body: <pre><code>Number = [0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19]    
  for n in range(0, 20):
        print(Number[n]+1\n)
  InputNum3 = input()
  Number[InputNum3] = ''.join(str('-'))
  </code></pre>
  
  <p>want:</p>
  
  <pre><code>1       2
       3
       4
       .... 20
  </code></pre>
  
  <p>input 2</p>
  
  <p>want: </p>
  
  <pre><code>1
        -
        3
        4...20
  </code></pre>
  
  <p>but the result is:</p>
  
  <blockquote>
    <p>TypeError: list indices must be integers or slices, not str</p>
  </blockquote>