title: The comments argument of genfromtxt in numpy
body: <p>I am learning the I/O functions of genfromtxt in numpy.
  I tried an example from the user guide of numpy. It is about the comments argument of genfromtxt.</p>
  
  <p><strong>Here is the example from the user guide of numpy:</strong></p>
  
  <pre><code>&gt;&gt;&gt; data = """#
  ... # Skip me !
  ... # Skip me too !
  ... 1, 2
  ... 3, 4
  ... 5, 6 #This is the third line of the data
  ... 7, 8
  ... # And here comes the last line
  ... 9, 0
  ... """
  &gt;&gt;&gt; np.genfromtxt(StringIO(data), comments="#", delimiter=",")
  [[ 1. 2.]
  [ 3. 4.]
  [ 5. 6.]
  [ 7. 8.]
  [ 9. 0.]]
  </code></pre>
  
  <p><strong>I tried below:</strong></p>
  
  <pre><code>data = """#                 \
      # Skip me !         \
      # Skip me too !     \
      1, 2                \
      3, 4                \
      5, 6 #This is the third line of the data    \
      7, 8                \
      # And here comes the last line  \
      9, 0                \
      """
  a = np.genfromtxt(io.BytesIO(data.encode()), comments = "#", delimiter = ",")
  print (a)
  </code></pre>
  
  <p><strong>Result comes out:</strong></p>
  
  <p>genfromtxt: Empty input file: "&lt;_io.BytesIO object at 0x0000020555DC5EB8>"
    warnings.warn('genfromtxt: Empty input file: "%s"' % fname)</p>
  
  <p>I know the problem is with data. Anyone can teach me how to set the data as shown in the example? 
  Thanks a lot.</p>