Originally Posted by Ene Uran

Since you want to save and later load an entire container object, the module pickle is what you want to use. Hre is a simple example:

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# pickle saves and loads any Python object intact
# via a byte stream, use cpickle for higher speed
 
import pickle
 
myList1 = [12, 52, 62, 02, 3.140, "Monte"]
print "Original list:"
print myList1
file = open("list1.dat", "w")
pickle.dump(myList1, file)
file.close()
file = open("list1.dat", "r")
myList2 = pickle.load(file)
file.close()
print "List after pickle.dump() and pickle.load():"
print myList2

# pickle saves and loads any Python object intact # via a byte stream, use cpickle for higher speed import pickle myList1 = [12, 52, 62, 02, 3.140, "Monte"] print "Original list:" print myList1 file = open("list1.dat", "w") pickle.dump(myList1, file) file.close() file = open("list1.dat", "r") myList2 = pickle.load(file) file.close() print "List after pickle.dump() and pickle.load():" print myList2

In your case you would pickle the students dictionary!

Originally Posted by vegaseat

What does your student dictionary look like just before you pickle.dump() it?
Also, you could write a small Python program that pickle.load() that file and looks at its contents.

Originally Posted by Ene Uran

Watch out when you start your program that your basic students dictionary does not override the newly loaded dictionary. Here is your code sample that works:

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import pickle
 
max_points = [25,25,50,25,100]
assignments = ["hw ch 1","hw ch 2","quiz   ","hw ch 3","test"]
 
try:
    file = open("students.dat", "r")
    students = pickle.load(file)
    file.close()
except:
    students = {"#Max":max_points}
    print "students.dat file not found, starting with", students
 
def print_menu():
    print "1. Add student"
    print "2. Remove student"
    print "3. Print grades"
    print "4. Record grade"
    print "5. Exit"
 
def print_all_grades():
    print "\t",
    for i in range(len(assignments)):
        print assignments[i],"\t",
    print
    keys = students.keys()
    keys.sort()
    for x in keys:
        print x,"\t",
        grades = students[x]
        print_grades(grades)
 
def print_grades(grades):
    for i in range(len(grades)):
        print grades[i],"\t\t",
    print
 
print_menu()
menu_choice = 0
while menu_choice != 5:
    print
    menu_choice = input("Menu Choice (1-6): ")
    if menu_choice == 1:
        name = raw_input("Student to add: ")
        students[name] = [0]*len(max_points)
    elif menu_choice == 2:
        name = raw_input("Student to remove: ")
        if students.has_key(name):
            del students[name]
        else:
            print "Student: ",name," not found"
    elif menu_choice == 3:
        print_all_grades()
    elif menu_choice == 4:
        print "Record Grade"
        name = raw_input("Student: ")
        if students.has_key(name):
            grades = students[name]
            print "Type the number of the grade to record"
            print "Type a 0 (zero) to exit"
            for i in range(len(assignments)):
                print i+1," ",assignments[i],"\t",
            print
            print_grades(grades)
            which = 1234
            while which != -1:
                which = input("Change which Grade")
                which = which-1
                if 0 <= which < len(grades):
                    grade = input("Grade: ")
                    grades[which] = grade
                elif which != -1:
                    print "Invalid Grade Number"
        else:
            print "Student not found"
    elif menu_choice != 5:
        print_menu()
 
print students  # test
# update students.dat file upon exit
file = open("students.dat", "w")
pickle.dump(students, file)
file.close()

import pickle max_points = [25,25,50,25,100] assignments = ["hw ch 1","hw ch 2","quiz ","hw ch 3","test"] try: file = open("students.dat", "r") students = pickle.load(file) file.close() except: students = {"#Max":max_points} print "students.dat file not found, starting with", students def print_menu(): print "1. Add student" print "2. Remove student" print "3. Print grades" print "4. Record grade" print "5. Exit" def print_all_grades(): print "\t", for i in range(len(assignments)): print assignments[i],"\t", print keys = students.keys() keys.sort() for x in keys: print x,"\t", grades = students[x] print_grades(grades) def print_grades(grades): for i in range(len(grades)): print grades[i],"\t\t", print print_menu() menu_choice = 0 while menu_choice != 5: print menu_choice = input("Menu Choice (1-6): ") if menu_choice == 1: name = raw_input("Student to add: ") students[name] = [0]*len(max_points) elif menu_choice == 2: name = raw_input("Student to remove: ") if students.has_key(name): del students[name] else: print "Student: ",name," not found" elif menu_choice == 3: print_all_grades() elif menu_choice == 4: print "Record Grade" name = raw_input("Student: ") if students.has_key(name): grades = students[name] print "Type the number of the grade to record" print "Type a 0 (zero) to exit" for i in range(len(assignments)): print i+1," ",assignments[i],"\t", print print_grades(grades) which = 1234 while which != -1: which = input("Change which Grade") which = which-1 if 0 <= which < len(grades): grade = input("Grade: ") grades[which] = grade elif which != -1: print "Invalid Grade Number" else: print "Student not found" elif menu_choice != 5: print_menu() print students # test # update students.dat file upon exit file = open("students.dat", "w") pickle.dump(students, file) file.close()