Create a Custom Python-Evaluated Input Problem

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Create a Standard Python Problem

You can use a script or answer tag format to create these problems. To create a custom Python-evaluated input problem using a <script> tag, follow these steps.

1. In the unit where you want to create the problem, select Problem under Add New Component.

2. In the problem editor, select Advanced problem types. Then select Custom Python-Evaluated Input.

3. In the component editor, modify the example as needed, following a structure similar to the one in the example below.

4. Select Save.

Sample Code: Enter any two integers for a given sum

Problem Code:

<problem>
<p>This question has two parts.</p>

<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>Part 1: Enter two integers that sum to 10. </p>
<customresponse cfn="test_add_to_ten">
        <textline size="10" correct_answer="3" label="Integer #1"/><br/>
        <textline size="10" correct_answer="7" label="Integer #2"/>
</customresponse>

<p>Part 2: Enter two integers that sum to 20. </p>
<customresponse cfn="test_add" expect="20">
        <textline size="10" label="Integer #1"/><br/>
        <textline size="10" label="Integer #2"/>
</customresponse>

<solution>
    <div class="detailed-solution">
        <p>Explanation</p>
        <p>For part 1, any two numbers of the form <i>n</i> and <i>10-n</i>,
        where <i>n</i> is any integer, will work. One possible answer would
        be the pair 0 and 10.</p>
        <p>For part 2, any two numbers of the form <i>n</i> and <i>20-n</i>, where <i>n</i> is any integer, will work. One possible answer would be the pair 1 and 19</p>
    </div>
</solution>
</problem>

Sample Code: Problem with Sample Answers

The following template includes answers that appear when the learner selects Show Answer.

<problem>

<script type="loncapa/python">
def test_add(expect,ans):
  a1=float(ans[0])
  a2=float(ans[1])
  return (a1+a2)== float(expect)
</script>

<p>Problem text</p>
<customresponse cfn="test_add" expect="20">
        <textline size="10" correct_answer="11" label="Integer #1"/><br/>
        <textline size="10" correct_answer="9" label="Integer #2"/>
</customresponse>

    <solution>
        <div class="detailed-solution">
          <p>Solution or Explanation Heading</p>
          <p>Solution or explanation text</p>
        </div>
    </solution>
</problem>

Sample Code: Problem with No Sample Answers

The following template does not return answers when the learner selects Show Answer. If your problem does not include answers for the learner to see, make sure to set Show Answer to Never in the problem component.

<problem>

<script type="loncapa/python">
def test_add(expect,ans):
  a1=float(ans[0])
  a2=float(ans[1])
  return (a1+a2)== float(expect)
</script>

<p>Enter two real numbers that sum to 20: </p>
<customresponse cfn="test_add" expect="20">
        <textline size="10"  label="Integer #1"/><br/>
        <textline size="10"  label="Integer #2"/>
</customresponse>

    <solution>
        <div class="detailed-solution">
          <p>Solution or Explanation Heading</p>
          <p>Solution or explanation text</p>
        </div>
    </solution>
</problem>

Create a Randomized Custom Python-Evaluated Input Problem

You can create a custom Python-evaluated input problem that randomizes variables in the Python code.

1. In the unit where you want to create the problem, select Problem under Add New Component.

2. In the problem editor, select Advanced problem types. Then select Custom Python-Evaluated Input.

3. In the component editor, modify the example as needed.

4. Select the randomization option that applies better to your exercise. The option selected will define when to randomize the variables specified in the associated Python script. The options you can select are Never, Always, Per Student, and On Reset.

Note

In the problem settings, you must set the Randomization value to something other than Never to have Python variables randomized. See Randomization for more information.

1. Select Save.

Example: Problem with Randomized Variables

The following example demonstrates using randomization with a Python-evaluated input problem.

Note

This example uses the method random.randint to generate random numbers. You can use any standard Python library for this purpose.

<problem>
  <p>Some problems in the course will utilize randomized parameters.
     For such problems, after you check your answer you will have the option
     of resetting the question, which reconstructs the problem with a new
     set of parameters.</p>
<script type="loncapa/python">
x1 = random.randint(0, 100)
x2 = random.randint(0, 100)
y = x1+x2
</script>
<p>Let (x_1 = $x1) and (x_2 = $x2). What is the value of (x_1+x_2)?</p>
<numericalresponse answer="$y">
  <responseparam type="tolerance" default="0.01%" name="tol"
    description="Numerical Tolerance"/>
  <textline size="10"/>
</numericalresponse>
<solution>
  <p><b>Explanation:</b></p>
</solution>
</problem>

Award Partial Credit for a Custom Python-Evaluated Input Problem

You can configure a custom Python-evaluated input problem so that learners who give a partially correct answer receive partial credit for the problem. You can award 50% of the points for the problem, or you can award a different percentage of points. For more information, see the following sections.

• Award Half Credit

• Award a Percentage of Credit

Award Half Credit

You can configure a problem to award 50% of the possible points. To provide a learner with a more granular score, see Award a Percentage of Credit.

The check function must return the value "Partial" in one of the following ways.

• Return the value "Partial" directly.

• Return the value "Partial" in the dictionary that is returned, in the following form.

  { 'ok': 'Partial', 'msg': 'Message' }

• Return the value "Partial" as part of the input list for multi-part problems.

  { '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'}
          ... ] }
  

With all of these options, True awards learners with 100% of the available points for the problem, 'Partial' with 50%, and False with 0%.

For more information about check function return values, see The check Function.

Award a Percentage of Credit

You can configure a problem to return a percent value as a grade. This method provides greater flexibility in assigning the learner a score than awarding half credit.

In the following example, the learner’s score equals the answer divided by 100.

The following code shows the configuration of this problem.

<problem>
<p>In the following problem, the learner receives a score that equals the
   answer / 100. If the learner's answer is greater than 100 or less than 0,
   the score equals 0.</p>

<script type="loncapa/python">

def give_partial_credit(expect, ans):
  ans = float(ans)
  if ans &gt; 100 or ans &lt; 0:
      # Assign a score of zero if the answer is less than zero or over 100.
      ans = 0
  grade = ans/100
  return {
      'input_list': [
         { 'ok': True, 'msg': 'Your grade is ' + str(ans) + '%', 'grade_decimal':grade},
      ]
  }
</script>

<p>Enter a number beween 0 and 100.</p>
<customresponse cfn="give_partial_credit">
  <textline points="100" size="40" label="Ans1"/><br/>
</customresponse>
</problem>

This example illustrates the following points.

• The points attribute of the <customresponse> element specifies that the question is worth 100 points.

• The give_partial_credit function checks that the answer is between 0 and 100, and if so divides the learner’s answer by 100 to determine the grade.

• The input_list that is returned specifies that:

  • The answer is acceptable and can receive partial or full credit, with the item 'ok': True.

  • The learner receives the message Your grade is followed by the percent grade, with the item 'msg': 'Your grade is ' + str(ans) + '%'.

  • The grade assigned is the learner’s answer divided by 100, with the item 'grade_decimal':grade.

You can enhance and apply this example for your own partial credit problems.

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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