title: How to plot 2d math vectors with matplotlib?
body: <p>How can we plot 2D math vectors with <code>matplotlib</code>? Does anyone have an example or suggestion about that? </p>
  
  <p>I have a couple of vectors stored as 2D <code>numpy</code> arrays, and I would like to plot them as directed edges. </p>
  
  <p>The vectors to be plotted are constructed as below:</p>
  
  <pre><code>import numpy as np
  # a list contains 3 vectors;
  # each list is constructed as the tail and the head of the vector
  a = np.array([[0, 0, 3, 2], [0, 0, 1, 1], [0, 0, 9, 9]]) 
  </code></pre>
  
  <hr>
  
  <p><strong>Edit:</strong></p>
  
  <p>I just added the plot of the final answer of <code>tcaswell</code> for anyone interested in the output and want to plot 2d vectors with matplotlib:
  <img src="https://i.stack.imgur.com/BkIId.png" alt="enter image description here"></p>