Guide to the Custom Python-Evaluated Input Problem

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The script tag format encloses a Python script that contains a “check function” in a <script> tag, and adds the cfn attribute of the <customresponse> tag to reference that function.

This section contains the following information about using the <script> tag.

The check Function

The check function in a <script> tag accepts two arguments.

• expect is the value of the expect attribute of <customresponse>. If expect is not provided as an argument, the function must have another way to determine if the answer is correct.

• answer is one of the following two options.

  • The value of the answer the learner provided, if the problem only has one response field.

  • An ordered list of answers the learner provided, if the problem has multiple response fields.

The check function can return any of the following values to indicate whether the learner’s answer is correct.

• True: Indicates that the learner answered correctly for all response fields.

• False: Indicates that the learner answered incorrectly. All response fields are marked as incorrect.

• "Partial": Indicates that the learner’s answer was partially correct. By default, the learner receives 50% of the points for the problem. For more information, see Award Half Credit.

• A dictionary of the form { 'ok': True, 'msg': 'Message' }. If the dictionary’s value for ok is set to True, all response fields are marked correct. If it is set to False, all response fields are marked incorrect. If it is set to "Partial", the learner receives 50% of the problem points. The msg is displayed below all response fields, and it can contain XHTML markup.

• A dictionary of the form:

  { 'overall_message': 'Overall message',
      'input_list': [
          { 'ok': True, 'msg': 'Feedback for input 1'},
          { 'ok': False, 'msg': 'Feedback for input 2'},
          { 'ok': 'Partial', 'msg': 'Feedback for input 3'}
          ... ] }
  

The last form is useful for responses that contain multiple response fields. It allows you to provide feedback for each response field individually, as well as a message that applies to the entire response.

Example with the Script Tag

In the following example, <customresponse> tags reference the test_add_to_ten and test_add functions that are in the <script> tag.

Important

Python honors indentation. Within the <script> tag, the def check_func(expect, ans): line must have no indentation.

<problem>

<script type="loncapa/python">

def test_add(expect, ans):
    try:
        a1=int(ans[0])
        a2=int(ans[1])
        return (a1+a2) == int(expect)
    except ValueError:
        return False

def test_add_to_ten(expect, ans):
    return test_add(10, ans)

</script>

<p>Enter two integers that sum to 10. </p>
<customresponse cfn="test_add_to_ten">
  <textline size="10"/><br/>
  <textline size="10"/>
</customresponse>

<p>Enter two integers that sum to 20: </p>
<customresponse cfn="test_add" expect="20">
  <textline size="40" correct_answer="11" label="Integer #1"/><br/>
  <textline size="40" correct_answer="9" label="Integer #2"/>
</customresponse>

<solution>
  <div class="detailed-solution">
    <p>Explanation</p>
    <p>Any set of integers on the line \(y = 10 - x\) and \(y = 20 - x\)
       satisfies these constraints.</p>
    <p>You can also add images within the solution clause, like so:</p>
    <img src="/static/images/placeholder-image.png"/>
  </div>
</solution>

</problem>

Example of the check Function Returning a Dictionary

The following example shows a check function that returns a dictionary.

def check(expect, answer_given):
    check1 = (int(answer_given[0]) == 1)
    check2 = (int(answer_given[1]) == 2)
    check3 = (int(answer_given[2]) == 3)
    return {'overall_message': 'Overall message',
                'input_list': [
                    { 'ok': check1, 'msg': 'Feedback 1'},
                    { 'ok': check2, 'msg': 'Feedback 2'},
                    { 'ok': check3, 'msg': 'Feedback 3'} ] }

The function checks that the user entered 1 for the first input, 2 for the second input, and 3 for the third input. It provides feedback messages for each individual input, as well as a message displayed below the entire problem.

Script Tag Attributes

The following table explains the important attributes and values in the preceding example.

<script type="loncapa/python">	Indicates that the problem contains a Python script.
<customresponse cfn="test_add_to_ten">	Indicates that the function test_add_to_ten is called when the learner checks the answers for this problem.
<customresponse cfn="test_add" expect="20">	Indicates that the function test_add is called when the learner checks the answers for this problem and that the expected answer is 20.
<textline size=”10” correct_answer=”3”/>	This tag includes the size, correct_answer, and label attributes. The correct_answer attribute is optional.

See also

About Custom Python-evaluated Input Problem (reference)

Create a Custom Python-Evaluated Input Problem (how to)

Maintenance chart

Review Date	Working Group Reviewer	Release	Test situation

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