title: Converting an empty string input to float
body: <p>I made a code like this to find the arithmetical mean for numbers the user has typed in but for some reason the program couldn't convert string to float in the end. What should I change?</p>
  
  <pre><code>print("I'm going to find the arithmetical mean! \n")
  jnr = 0; sum = 0
  negative = "-"
  while True:
      x = input(f"Type in {jnr}. nr. (To end press Enter): ")
      if negative not in x:
          jnr += 1
      elif negative in x:
          pass
      elif x == "": break
      sum = sum + float(x)
  
  print("Aritmethmetical mean for these numbers is: "+str(round(sum/(jnr-1), 2)))
  </code></pre>
  
  <p>I got his Error :</p>
  
  <blockquote>
    <p>Traceback (most recent call last): File
    "C:\Users\siims\Desktop\Koolitööd\individuaalne proge.py", line 11, in
     sum = sum + float(x) ValueError: could not convert string to
    float</p>
  </blockquote>