title: convert a list to an array, out put has no comma
body: <p>I tried to convert a list to an array, but the output I got has no comma.</p>
  <pre><code>%%writefile tem2504.txt
  1 2 3 4 5 6
  2 3 5 8 7 9
  
  data = []
  with open('tem2504.txt') as f:
      for line in f:
          numbers = line.split()
          print(numbers)
          print('hello')
          for number in numbers:
              data.append(float(number))
  print(data)
  print(type(data))
  print(np.array(data))
  print(type(np.array(data)))
  </code></pre>
  <p>But the out put I got has no comma between the numbers: [1. 2. 3. 4. 5. 6. 2. 3. 5. 8. 7. 9.]</p>
  <pre><code>['1', '2', '3', '4', '5', '6']
  hello
  ['2', '3', '5', '8', '7', '9']
  hello
  [1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 2.0, 3.0, 5.0, 8.0, 7.0, 9.0]
  &lt;class 'list'&gt;
  [1. 2. 3. 4. 5. 6. 2. 3. 5. 8. 7. 9.]
  &lt;class 'numpy.ndarray'&gt;
  </code></pre>
  <p>Why is that?
  Thank you!</p>