[solved] Count number of times something happens in a while loop

Comments

• sebastiaan

  July 2014 edited 1:01PM

  Hi Darby,

  I'm assuming you're working with a script from the discussion below, or some variation of it, but the basic principle should work anywhere.

  • http://forum.cogsci.nl/index.php?p=/discussion/1051

  What you could do is use a variable nClickErr that is incremented (+= 1) every time that an erroneous click is registered. This will give you a running total of the number of times that this happens during the entire experiment. Just read the code below carefully, and the logic should be clear (it's pretty simple).

  Is this what you had in mind?

  Cheers!
  Sebastiaan

  exp.set('xRed', 0)
  exp.set('yRed', 0)
  
  from openexp.mouse import mouse
  from math import sqrt
  
  # Create a mouse object
  my_mouse = mouse(exp, visible=True)
  
  # The maximum error from the target center
  maxClickErr = 100
  
  # Get the number of click errors and reset to 0 if this variable hasn't been
  # defined yet
  nClickErr = self.get_check('nClickErr', default=0)
  
  # Get the coordinates of the display center, which are necessary to convert
  # from top-left to center-based coordinates.
  xc = self.get('width') / 2
  yc = self.get('height') / 2
  
  # Loop until we get a hit (i.e. a correct mouse click)
  while True:
      button, pos, timestamp = my_mouse.get_click()
      cursor_x, cursor_y = pos
      # Determine x and y error
      dx = cursor_x - xc - self.get('xRed')
      dy = cursor_y - yc - self.get('yRed')
      # Break the loop if there is a hit (use Pythagoras for click error)
      clickErr = sqrt(dx**2 + dy**2)
      if clickErr <= maxClickErr:
          # Increase the number of click errors
          nClickErr += 1
          break
  # Set the number of click errors as an experiment variable.
  exp.set('nClickErr', nClickErr)
  

  
  
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• Darby

  July 2014 edited 1:01PM

  Thanks so much Sebastiaan. As usual, this works great.