gistfile1.py

location_target = self.get('location_target')
resp = self.get("response")

# Here you determine whether the response is correct, like
# the scripts posted earlier by yourself and Edwin. 
# The only addition is the else-statement at the end,
# to make sure that RT should be included in the averages 
# ig location_target is not "none".
if location_target == "none": # No-trial		
	# In OpenSesame 0.27, no-responses are saved as 'None'
	if resp in ('timeout', 'None'):
		correct = 1
	else:
		correct = 0
else: # Go-trial	
	correct = self.get('correct') # Assumed that 'correct' for go-trials is set in the GUI
	# If trial is a go-trial, add trial-RT to the RT-list
	lRT.append(self.get('response_time'))

# Add 'correct' always to the acc-list:
lCorrect.append(correct)

# Calculate averages and set them as my_avg_rt and my_acc,
# which you can simply use in a feedback display
if len(lRT) > 0:
	exp.set('my_avg_rt', sum(lRT)/len(lRT))
else:
	exp.set('my_avg_rt', 'undefined')	
if len(lCorrect) > 0:
	exp.set('my_acc', 100.*sum(lCorrect)/len(lCorrect))
else:
	exp.set('my_acc', 'undefined')