Checking match on two ordered lists-CodePudding

I will give the specific case and the generic case so we can help more people:

I have a list of ordered lists and another list with the same length as each ordered list. Each list in the list of lists is students' answers from a large-scale evaluation, and the second is the correct answers from the test. I need to check the % of right answers, AKA how many matches are between each item in each of the lists in order. The output should be a list where 1 means there is a match, and 0 there is no match.

Example:

list1 = [['A', 'B', 'C', 'A'], ['A', 'C', 'C', 'B']]
list2 = ['A', 'B', 'C', 'A']
result = [[1, 1, 1, 1],[1, 0, 1, 0]

Thank you!

CodePudding user response：

You can use a nested list comprehension, like the following

results = [[int(value == list2[index]) for index, value in enumerate(i)] for i in list1]

This iterates over each element of list1, iterating over each element, and checking if its corresponding pair in list2 is the same.

enumerate is used to avoid range(len(list1)), which is not recommended for stylistic reasons. Equality == returns a boolean, and we cast this to an int via int, which turns True into 1 and False into 0.

Output:

>>> list1 = [['A', 'B', 'C', 'A'], ['A', 'C', 'C', 'B']]
>>> list2 = ['A', 'B', 'C', 'A']
>>> results = [[int(value == list2[index]) for index, value in enumerate(i)] for i in list1]
>>> print(results)
[[1, 1, 1, 1], [1, 0, 1, 0]]

Happy coding!

CodePudding user response：

If you want to write it as a one-liner using list comprehensions

output = [[int(answer_given == correct_answer) for answer_given, correct_answer in zip(student, list2)] for student in list1]

CodePudding user response：

The others have done a fine job detailing how this can be done with list comprehensions. The following code is a beginner-friendly way of getting the same answer.

final = []

# Begin looping through each list within list1
for test in list1:

    # Create a list to store each students scores within
    student = []
    for student_ans, correct_ans in zip(test, list2):

        # if student_ans == correct_ans at the same index...
        if student_ans == correct_ans:
            student.append(1)
        else:
            student.append(0)
    
    # Append the student list to the final list
    final.append(student)