plt.show() does nothing when used for the second time : <p>I am just starting to learn data science using python on Data Camp and I noticed something while using the functions in matplotlib.pyplot</p>

<pre><code>import matplotlib.pyplot as plt

year = [1500, 1600, 1700, 1800, 1900, 2000]
pop = [458, 580, 682, 1000, 1650, 6,127]

plt.plot(year, pop)

plt.show() # Here a window opens up and shows the figure for the first time
</code></pre>

<p>but when I try to show it again it doesn't..</p>

<pre><code>plt.show() # for the second time.. nothing happens
</code></pre>

<p>And I have to retype the line above the <code>show()</code> to be able to show a figure again</p>

<p>Is this the normal thing or a problem?</p>

<p>Note: I am using the REPL</p>
