OpenSesame code snippets

snippets.py

# ***
# * Continuously poll the keyboard
# ***

from openexp.keyboard import keyboard
my_keyboard = keyboard(self.experiment, timeout=20)
start_time = self.time()
while True:
    # Perform some task here
    key, end_time = my_keyboard.get_key()
    if key != None:
        break
self.experiment.set("response", my_keyboard.to_chr(key))
self.experiment.set("response_time", end_time-start_time)

# ***
# * Copy the canvas from a sketchpad item
# ***

from openexp.canvas import canvas
my_canvas = canvas(self.experiment)
my_canvas.copy(self.experiment.items["name_of_sketchpad"].canvas)

# ***
# * Getting and setting variables
# ***

# Setting variables
self.experiment.set("my_variable", "my_value") # Preferred
self.experiment.my_variable = "my_value" # Not preferred
# Getting variables
print self.get("my_variable") # Preferred
print self.experiment.my_variable # Not preferred
# Checking whether a variable exists
if self.has("my_variable"):
    print "My variable exists"

# ***
# * Overlay multi-character text input over a sketchpad
# ***

from openexp.canvas import canvas
from openexp.keyboard import keyboard
my_canvas = canvas(self.experiment)
my_keyboard = keyboard(self.experiment)
resp = "" # Here we store the response
while True:
    # Get a keyboard response
    key, time = my_keyboard.get_key()
    # keyboard.to_chr() converts the keycode to a description,
    # like 'space' or 'return'. If return is pressed the loop
    # should be exited.
    if my_keyboard.to_chr(key) == "return":
        break
    # Handle backspace by removing the last character
    if my_keyboard.to_chr(key) == "backspace":
        resp = resp[:-1]
    else:
        # The built-in chr() converts the keycode to a character,
        # like ' ' and '/'.
        resp += chr(key)
    # Copy the canvas from a sketchpad called 'my_sketchpad' and
    # overlay the response
    my_canvas.copy(self.experiment.items["my_sketchpad"].canvas)
    my_canvas.text(resp)
    my_canvas.show()
# Save the response
self.experiment.set("response", resp)

# ***
# * Print a debugging message
# ***

print "This is a debug message"

# ***
# * Write a custom message to the log-file
# ***

self.log("This is a custom log message")

# ***
# * Reverse the text in all sketchpad, feedback, text_display, and text_input
# * items. Supports Unicode characters.
# ***

from PyQt4.QtCore import QString
for item in self.experiment.items.values():
	if item.item_type in ['sketchpad', 'feedback']:
		for element in item.items:
			if 'text' in element:
				s = element['text']
				s = self.usanitize(QString(self.unsanitize(s)[::-1]))
				element['text'] = s
	elif item.item_type in ['text_input']:
		s = item._question
		s = self.usanitize(QString(self.unsanitize(s)[::-1]))
		item._question = s
	elif item.item_type in ['text_display']:
		s = item.content
		s = self.usanitize(QString(self.unsanitize(s)[::-1]))
		item.content = s

# ***
# * Keep track of averages, for example to be used in a feedback item
# ***

my_response_time = 1000 # Indicates response time
is_correct = True # Indicates whether the response is correct

self.experiment.total_responses += 1
if is_correct:
	self.experiment.total_correct += 1
self.experiment.total_response_time += my_response_time
self.experiment.acc = 100. * self.experiment.total_correct / self.experiment.total_responses
self.experiment.avg_rt = self.experiment.total_response_time / self.experiment.total_responses
self.experiment.accuracy = self.experiment.acc
self.experiment.average_response_time = self.experiment.avg_rt