title: How to evaluate a string and keep precision in Python
body: <p>I’m trying to get a more precise result from this code:</p>
  
  <pre><code>a = str(10**20+10**-20)
  b = eval(a)
  </code></pre>
  
  <p>I want to obtain around 42 decimal places so Python doesn’t round it to 1e+20.</p>