Mivan 2025 Python歌单生成器

"""
Student_dictionary.py

A dictionary of students that holds their names, ethnicity and age
Allows the user to add and delete a student and change their age
Can list the ethnicity of all the students and all the students of a certain age
"""

def add_student(name, ethnicity, age):
    """
    Add a student to the records.

    name - string: the name of the student.
    ethnicity - string: that is the ethnicity of the student.
    age - int: the age of the student.
    """

    names.append(name)
    ethnicities.append(ethnicity)
    ages.append(age)

    return names, ethnicities, ages

def  change_age(name, new_age, ages):
    """
    Change the age of a student.

    name - string: the name of the studnet whoes age to change
    new_age - int: the new age of the student
    ages - list: the ages of all students
    """
    #what if students do not exsit?
    student_index = names.index(name) # look for index of student

    # change the student's age to the new_age
    ages[student_index] = new_age
    print("Age for {} updated to {}.".format(name, new_age))

    return ages

def delete_age(name, names, ethnicities, ages):
    """
    Delete a student from the records.

    name - string: the name of the student to delete
    names - list: the list of student names
    ethnicities - lists: the list of student ethnicities.
    ages - list: the list of student ages.
    """
    studnet_index = names.index(name) # look for index of student

    #delete the student based on the idex. ? what if students are not there?
    del names[student_index]
    del ethnicities[student_index]
    del ages[student_index]
    print("{} deleted from records.".format(name))

def list_all_ethnicities():
    """
    List all unique ethnicities of students
    """
    print("Ethnicities of all students")

    # Holds all ethnicities
    seen_ethnicities = []

    #Search through the ethnicities
    for ethnicity in ethnicities:
        #if it has not been seen add to list
        if ethnicity not in seen_ethnicities:
            print(ethnicity)
            seen_ethnicities.append(ethnicity)
            
def find_students_by_age(target_age):
    """
    Find students of a specific age.

    target_age - int: the age to search for.
    """
    # Holds list of students at target age
    students = []

    # Loop over list of students
    for i in range(len(names)):
        # Check their age matches the target age and add to list
        if ages[i] == target_age:
            students.append(names[i])

        # Show all students who are at target age
    for student in students:
        print(student)

def main():
    """Main function to run the program.
    """
    while True:
        print("\nMenu:")
        print("1. Add a student")
        print("2. Change age for a student")
        print("3. Delete a student")
        print("4. List all ethnicities")
        print("5. Find students by age")
        print("6. Exit")

        choice = input("Enter your choice: ")

        if choice == "1":
            name = input("Enter student's name: ")
            ethnicity = input("Enter student's ethnicity: ")
            age = int(input("Enter student's age: "))
            names, ethnicities, ages = add_student(name, ethnicity, age) #update students
        elif choice == "2":
            name = input("Enter student's name: ")
            new_age = int(input("Enter student's new age: "))
            ages = change_age(name, new_age, ages) # update the ages list
        elif choice == "3":
            name = input("Enter student' name: ")
            names, ethnicities, ages = delete_student(name) # update students
        elif choice == "4":
            list_all_ethnicities()
        elif choice == "5":
            target_age = int(input("Enter age for search for: "))
            find_students_by_age(target_age)
        elif choice == "6":
            print("Exiting program.")
            break
        else:
            print("Invalid choice. Please enter a number from 1 to 6.")

if __name__ =="__main__":
    # Parallel list of student attributes
    names = []
    ethnicities = []
    ages = [] # The three parallel lists are not well-structured, thinking of addressing it.

    main()

""" Using dictionaries to deal with students question"""

def add_student(students):
    """add a new student to the system"""
    name = input("Enter student name: ").strip().lower()
    if name in students:
        print("Student already exists!")

    ethnicity = input("Enter student ethnicity: ").strip().lower()
    age = get_valid_age()

    students[name] = {
        'ethnicity': ethnicity,
        'age': age
        }
    print("Student {} added successfully.".format(name))
def update_student_age(students):
    """Update the age of an existing student."""
    name = input("Enter student name to update age: ").strip()
    if name not in students:
        print("Student not found!")
    else:
        new_age = get_valid_age()
        students[name]['age'] = new_age
        print("Age updated for {} to {}".format(name, new_age))

def delete_student(students):
    """Remove a student from the system"""
    name = input("Enter student name to delete: ").strip()
    if name not in students:
        print("Students not found!")
    else:
        del students[name]
        print("Student {} deleted successfully!".format(name))

def list_all_ethnicities(students):
    """Display all unique ethnicities in the system"""
    for student in students.values():
        ethnicities = student['ethnicity']
        print(ethnicities)

def find_by_ethnicity(students):
    """Find and display students of a specific ethnicity"""
    ethnicity = input("enter ethnicity to search for: ").strip()
    names = []

    for name, eth in students.items():
        if eth['ethnicity'] == ethnicity.lower():
            names.append((name, eth['age']))
    print(names)


def get_valid_age():
    """Helper function to get and validate age input"""
    MAX_AGE = 120
    MIN_AGE = 0
    while True:
        try:
            age = int(input("Enter age: "))
            if MAX_AGE > age > MIN_AGE:
                return age
            else:
                print("Age must be in the range of 0-120")
            
        except ValueError:
            print("Age must be a number! Try again.")
    

def print_all_students(students):
    """ Print all keys in the dictionary"""
    print(students)

def find_by_age(students):
    """Find and display students of a specific age"""
    age = input("enter ethnicity to search for: ").strip()
    names = []

    for name, age_student in students.items():
        if age_student['age'] == age.lower():
            names.append((name, age_student['ethnicity']))
    print(names)
    

def main():
    students = {}  # Main dictionary to store student data
    
    while True:
        print("\nStudent Management System")
        print("1. Add a student")
        print("2. Update student age")
        print("3. Delete a student")
        print("4. List all ethnicities")
        print("5. Find students by ethnicity")
        print("6. Find students by age")
        print("7. Print all students")
        print("8. Exit")
        
        choice = input("Enter your choice (1-7): ")
        
        if choice == "1":
            add_student(students)
        elif choice == "2":
            update_student_age(students)
        elif choice == "3":
            delete_student(students)
        elif choice == "4":
            list_all_ethnicities(students)
        elif choice == "5":
            find_by_ethnicity(students)
        elif choice == "6":
            find_by_age(students)
        elif choice == "7":
            print_all_students(students)
        elif choice == "8":
            print("Exiting the system. Goodbye!")
            break
        else:
            print("Invalid choice. Please enter a number between 1-7.")

if __name__ == "__main__":
    main()