SingleChoice-type elements save data as integers - how can I access the corresponding text?

[jobrachem]

Sometimes it would be much more convenient to work with the selected text of a SingleChoice element, rather than an integer. How can I access the text?

[jobrachem]

Here's an example with extensive comments that walks you through the steps:

import alfred3 as al
exp = al.Experiment()

@exp.member
class Demo(al.Page):
    
    def on_exp_access(self):
        self += al.SingleChoice("a", "b", name="my_single_choice_element")


@exp.member
class Show(al.Page):
    
    def on_first_show(self):
        # This is the SingleChoice element instance
        # The pattern is: self.exp.PAGENAME.ELEMENTNAME
        element = self.exp.Demo.my_single_choice_element 
        
        # This is the number of the selected choice, starting at 1
        selected_choice_number = element.input  
        
        # This is a list of the available choices. These are instances of a 
        # private helper class _Choice
        available_choices = element.choices 
        
        # We use the number of the selected choice to access the 
        # corresponding object. We have to subtract 1, because lists 
        # start indexing at 0, but our selected_choice_number
        # starts at 1.
        choice = available_choices[selected_choice_number - 1]

        # Now we extract the "label" from the choice instance.
        # The label is what is being displayed to participants, in this
        # case the text.
        selected_text = choice.label
        

        self += al.Text(selected_text)  # Displays the result

if __name__ == "__main__":
    exp.run()

To make the code a bit more organized, we can extract much of the functionality to its own function. In the following code example, I have put the relevant lines of code into the function extract_input_label(). In my Show page, I can now simply call this function and receive my value:

import alfred3 as al
exp = al.Experiment()


def extract_input_label(element) -> str:
        """
        Extracts the selected text from a SingleChoice element and
        similar classes like SingleChoiceButtons.
        """
        selected_choice_number = element.input  
        available_choices = element.choices 
        choice = available_choices[selected_choice_number - 1]
        return choice.label


@exp.member
class Demo(al.Page):
    
    def on_exp_access(self):
        self += al.SingleChoice("a", "b", name="my_single_choice_element")
    

@exp.member
class Show(al.Page):
    
    def on_first_show(self):
        element = self.exp.Demo.my_single_choice_element 
        selected_text = extract_input_label(element)  # Here we use the function defined above
        
        self += al.Text(selected_text)  # Displays the result


if __name__ == "__main__":
    exp.run()