Python Dictionary Exercise Solution

This solution follows the exercise on dictionary data from CSV-style rows. It keeps the original exercise approach of working without the csv module, while using context managers so files are closed automatically.

Sample student.csv data

1,Ravi,20,30,40,120
2,Raju,30,40,50,130
3,Alex,40,50,60,140
4,Ronn,50,60,70,150

1. Create student.csv from user input

with open('student.csv', 'w', encoding='utf-8') as file:
    for student_id in range(1, 5):
        name = input('Student name: ')
        physics = input('Physics marks: ')
        chemistry = input('Chemistry marks: ')
        math = input('Math marks: ')
        attendance = input('Days present: ')
        row = f'{student_id},{name},{physics},{chemistry},{math},{attendance}\n'
        file.write(row)

Opening the file in w mode makes repeated practice runs predictable instead of appending duplicate records.

2. Read the file and create a dictionary

students = {}

with open('student.csv', 'r', encoding='utf-8') as file:
    for record in file:
        parts = record.rstrip('\n').split(',')
        student_id = parts[0]
        students[student_id] = parts[1:]

print(students)
print(students['2'])

The value stored for each ID is a list in this order: name, Physics, Chemistry, Math and attendance. The rstrip() call removes the line break before splitting the row.

3. Create student1.csv from the dictionary

with open('student1.csv', 'w', encoding='utf-8') as file:
    for student_id, details in students.items():
        row = ','.join([student_id, *details]) + '\n'
        file.write(row)

4. Create student2.csv after reducing Physics by 2

with open('student2.csv', 'w', encoding='utf-8') as file:
    for student_id, details in students.items():
        name, physics, chemistry, math, attendance = details
        physics = str(int(physics) - 2)
        row = ','.join([student_id, name, physics, chemistry, math, attendance]) + '\n'
        file.write(row)

This corrects the intended exercise operation by changing the Physics field specifically. int() converts the mark for arithmetic and str() converts it back for file output.

Download the original exercise ZIP / notebook ⇓

Subhendu Mohapatra

Author & Instructor at plus2net

I write and maintain practical tutorials on Python, PHP, SQL, JavaScript, HTML, jQuery, and web development at plus2net. The tutorials focus on clear explanations, working examples, and code that readers can test and adapt while learning.

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