title: Different colours for arrows in quiver plot
body: <p>I am plotting an arrow graph and my code uses an external file as follows:</p>
  
  <pre><code>import numpy as np
  import matplotlib.pyplot as plt
  import matplotlib as mpl
  from pylab import rcParams
  
  data=np.loadtxt(r'data.dat')
  
  x = data[:,0] 
  y = data[:,1] 
  u = data[:,2] 
  v = data[:,3] 
  
  
  plt.quiver(x, y, u, v, angles='xy', scale_units='xy', scale=1, pivot='mid',color='g')
  </code></pre>
  
  <p>The data file basically looks like :</p>
  
  <pre><code>1 1 0 0
  0 1 1 0
  0 1 1 0
  1 1 0 1
  </code></pre>
  
  <p>Is there a way to plot this with different colours for the different arrow directions?</p>
  
  <p>Ps.: I have got a lot more arrows in my data file in a not very logical sentence like the one I am using as example.</p>