title: How to plot graph using float values with matplotlib
body: <p>I prepared following code:</p>
  <pre><code>import matplotlib.pyplot as plt
  import numpy as np
  
  x1 = np.array([100, 400, 1600, 6400,25600, 102400])
  y4 = np.array([868, 3179, 3418, 4195, 4941, 5000])
  #y4 = np.array([-38.,28.,273.,1256., 5164.,20830.])
  print(y4.dtype)  #int32
  plt.figure(0)
  plt.plot(y4,x1,label='label1')
  plt.ylabel('y-label')
  plt.legend(['label1'])
  plt.savefig('test.png', bbox_inches='tight')
  </code></pre>
  <p>It outputs following graph:</p>
  <p><a href="https://i.stack.imgur.com/LcrK0m.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/LcrK0m.png" alt="enter image description here" /></a></p>
  <p>If I use commented <code>y4</code>:</p>
  <pre><code>#y4 = np.array([868, 3179, 3418, 4195, 4941, 5000])
  y4 = np.array([-38.,28.,273.,1256., 5164.,20830.])
  print(y4.dtype)  #float64
  </code></pre>
  <p>It plots straight line:</p>
  <p><a href="https://i.stack.imgur.com/axnmhm.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/axnmhm.png" alt="enter image description here" /></a></p>
  <p>Why float64 y-axis values does not work and plot all six points?</p>
  <p>PS: I am on python 3.8.3</p>