title: What do 1_000 and 100_000 mean?
body: <p>Since I've been learning Python, I've sometimes seen beginner examples that look like this:</p>
  
  <pre><code>sum_sq = [None] * 1_000
  </code></pre>
  
  <p>I've bought three Python books and none have mentioned what the <code>1_000</code> and <code>100_000</code> means that I'm seeing in these examples.</p>
  
  <p>My question is: is <code>1_000</code> the same as 1,000? And if so, why do they write it as <code>1_000</code>? Does it have a special function that 1,000 does not? Things like: </p>
  
  <pre><code>if __name__ == __main__ 
  </code></pre>
  
  <p>have sensible reasons for using the underscore and I can't see a reason why <code>1_000</code> is used. </p>