Python program to display all second lowest grade student name from nested list

Suppose we have the names and grades for each student in a nested list, we have to display the names of any students having the second lowest grade. If there are more than one students with the second lowest grade, reorder these in alphabetical order and print each name on a new line.

So, if the input is like students = [['Amal',37],['Bimal',37],['Tarun',36],['Akash',41],['Himadri',39]], then the output will be Amal and Bimal, both having the second lowest score of 37, displayed in alphabetical order.

Algorithm Steps

To solve this, we will follow these steps ?

• Find the minimum grade among all students
• Filter out students with the minimum grade
• Find the minimum grade from the remaining students (second lowest overall)
• Extract and sort student names with the second lowest grade alphabetically
• Display each name on a new line

Example

Let us see the following implementation to get better understanding ?

def solve(students):
    min_mark = min(x[1] for x in students)
    students = [x for x in students if x[1] > min_mark]
    min2_mark = min(x[1] for x in students)
    students = sorted([x[0] for x in students if x[1] == min2_mark])
    for x in students:
        print(x)

students = [['Amal',37],['Bimal',37],['Tarun',36],['Akash',41],['Himadri',39]]
solve(students)

Amal
Bimal

How It Works

Let's trace through the algorithm with our example data:

1. Initial data: [['Amal',37],['Bimal',37],['Tarun',36],['Akash',41],['Himadri',39]]
2. Find minimum grade: min_mark = 36 (Tarun's grade)
3. Filter out minimum: [['Amal',37],['Bimal',37],['Akash',41],['Himadri',39]]
4. Find second lowest: min2_mark = 37
5. Extract and sort names: ['Amal', 'Bimal'] (already in alphabetical order)

Alternative Implementation

Here's a more concise version using set operations ?

def find_second_lowest(students):
    grades = sorted(set(x[1] for x in students))
    second_lowest = grades[1]
    
    names = [x[0] for x in students if x[1] == second_lowest]
    return sorted(names)

students = [['Amal',37],['Bimal',37],['Tarun',36],['Akash',41],['Himadri',39]]
result = find_second_lowest(students)

for name in result:
    print(name)

Amal
Bimal

Conclusion

This program efficiently finds students with the second lowest grade by first identifying the minimum grade, filtering it out, then finding the next minimum. The names are sorted alphabetically before display, ensuring consistent output order.