Develop Reference

Python pickles not storing data

I am trying to create a registrar system through Python with pickles. I have gotten the system to record user input, but it does not save it for future implementations of the program.
Here is the code that will start the program:
import datetime
import pandas as pd
import pickle as pck
import pathlib
from pathlib import *
from registrar import *
prompt = "Please select an option: \n 1 Create a new course \n 2 Schedule a new course offering \n 3 List this school's course catalogue \n 4 List this school's course schedule \n 5 Hire an instructor \n 6 Assign an instructor to a course \n 7 Enroll a student \n 8 Register a student for a course \n 9 List this school's enrolled students \n 10 List the students that are registered for a course \n 11 Submit a student's grade \n 12 Get student records \n 13 Exit"
farewell = "Thank you for using the Universal University Registrar System. Goodbye!"
print ("Welcome to the Universal University Registration System.")
print ("\n")
try: #As long as CTRL-C has not been pressed, or 13 not been input by user.
input_invalid = True
while input_invalid:
inst = input("Please enter the name of your institution. ").strip()
domain = input("Please enter the domain. ").strip().lower()
if inst == "" or domain == "":
print("Your entry is invalid. Try again.")
else:
input_invalid = False
schoolie = Institution(inst, domain)
if Path(inst + '.pkl').exists() == False:
with open(inst + '.pkl', 'r+b') as iptschool:
schoolie = pck.load(iptschool)
while True:
print (prompt)
user_input = input("Please enter your choice: ")
try:
user_input = int(user_input)
if user_input < 1 or user_input > 14: #UserInput 14: on prompt.
raise ValueError("Please enter a number between 1 and 13, as indicated in the menu.")
except ValueError:
print("Not a valid number. Please try again.")
if user_input == 1: #Create a new course
input_invalid2 = True #Ensure that the user actually provides the input.
while input_invalid2:
input_name = input("Please enter a course name: ").strip()
input_department = input("Please enter the course's department: ").strip()
input_number = input("Please enter the course's number (just the number, not the departmental prefix): ").strip()
try:
input_number = int(input_number)
except ValueError:
print ("Please print an integer. Try again.")
input_credits = input("Please enter the number of credits awarded for passing this course. Please use an integer: ").strip()
try:
input_credits = int(input_credits)
except ValueError:
print ("Please print an integer. Try again.")
if input_name != "" and input_department != "" and input_number and input_credits:
input_invalid2 = False #Valid input
else:
print("One or more of your entries is invalid. Try again.")
added_course = Course(input_name, input_department, input_number, input_credits)
for course in schoolie.course_catalog:
if course.department == input_department and course.number == input_number and course.name == input_name:
print("That course is already in the system. Try again.")
input_invalid2 == True
if input_invalid2 == False:
schoolie.add_course(added_course)
print ("You have added course %s %s: %s, worth %d credits."%(input_department,input_number,input_name, input_credits))
And here is the second option, which SHOULD reveal that it is stored, but it does not.
elif user_input == 2: #Schedule a course offering
input_invalid2 = True #Ensure that the user actually provides the input.
while input_invalid2:
input_department = input("Please input the course's department: ").strip()
input_number = input("Please input the course's number: ").strip()
course = None
courseFound = False
for c in schoolie.course_catalog:
if c.department == input_department and c.number == input_number: #Course found in records
courseFound = True
course = c
input_section_number = input("Please enter a section number for this course offering: ").strip()
input_instructor = input("If you would like, please enter an instructor for this course offering: ").strip()
input_year = input("Please enter a year for this course offering: ").strip()
input_quarter = input("Please enter the quarter in which this course offering will be held - either SPRING, SUMMER, FALL, or WINTER: ").strip().upper()
if input_course != "" and input_course in schoolie.course_catalog and input_section_number.isdigit() and input_year.isdigit() and input_quarter in ['SPRING', 'SUMMER', 'FALL', 'WINTER'] and input_credits.isdigit():
if input_instructor != "": #Instructor to be added later, if user chooses option 6.
added_course_offering = CourseOffering(c, input_section_number, None, input_year, input_quarter)
else:
added_course_offering = CourseOffering(c, input_section_number, input_instructor, input_year, input_quarter)
schoolie.add_course_offering(added_course_offering)
input_invalid2 = False #Valid input
print ("You have added course %s, Section %d: %s, worth %d credits."%(input_course,input_section_number,input_name, input_credits))
else:
print("One or more of your entries is invalid. Try again.")
if courseFound == False: #If course has not been found at the end of the loop:
print("The course is not in our system. Please create it before you add an offering.")
break
By the way, I think I have the system closing properly. Correct me if I'm wrong:
elif user_input == 13: #Exit
with open(inst + '.pkl', 'wb') as output:
pck.dump(schoolie, output, pck.HIGHEST_PROTOCOL)
del schoolie
print (farewell)
sys.exit()
except KeyboardInterrupt: #user pushes Ctrl-C to end the program
print(farewell)
I believe that there is something wrong with the way that I am setting up the pickles files. I'm creating them, but I seem not to be putting data into them.
I apologize for the long-winded nature of this question, but I hope that the details will help you understand the problems that I've been having. Thanks in advance for the help!

it seems you may have dump and load reversed: (from the docs)
Signature: pck.load(file, *, fix_imports=True, encoding='ASCII', errors='strict')
Docstring:
Read and return an object from the pickle data stored in a file.
Signature: pck.dump(obj, file, protocol=None, *, fix_imports=True)
Docstring:
Write a pickled representation of obj to the open file object file.

With all those lines of code, it does get a little confusing, but I don't see any code that is pickling and writing the objects to a file.
Before anything else, you should assign the file to a variable so you can reference it. To do this, you'll have code similar to this:MyFile = open("FileName.extension","wb"). MyFile can be any name you want, it will be what you use later to reference the file. FileName is the name of the file itself. This is the name it will have in File Explorer. .extension is the file's extension, specifying the type of file. You should use .dat for this. wb is the file access mode. "w" means write, and "b" means binary. (Pickled objects can only be stored in a binary file.)
To write the pickled objects, you'll need this code:pck.dump(object,MyFile). (Usually, you would use pickle.dump(object,MyFile), but you imported pickle as pck.)
After writing the data to the file, you'll want to retrieve it. To do this, the "wb" instance of MyFile needs to be closed like this:MyFile.close(). Then you'll need to re-open the file in read mode using the following code:MyFile = open("FileName.extension","rb") Then you would use this:object = pickle.load(MyFile) to read the data. In the preceding example, (the load function), your object must have the same name as when you pickled it using the dump function. (pck.dump(object,MyFile))
In the end, you'll end up with something similar to this:
if writing conditions are true:
MyFile = open("FileName.dat","wb")
pickle.dump(object,MyFile) # This will be repeated for each object.
MyFile.close()
if reading conditions are true:
MyFile = open("FileName.dat","rb")
object = pickle.load(MyFile) # This will be repeated for each object.
MyFile.close()
I'm sorry if this wasn't the answer you wanted. Because of all those lines of code, it is somewhat hard to understand. I need clarification to give a better answer.

How would I use a while loop so that if they enter a number it would ask them the again?

fn = input("Hello, what is your first name?")
firstname = (fn[0].upper())
ln = input("Hello, what is your last name?")
lastname = (ln.lower())
I want fn to be on a loop so that if they enter their a number instead of letters, it would repeat the question

I guess you need something like this
final_fn = ""
while True:
fn = input("Hello, what is your first name?")
if valid(fn):
final_fn = fn
break
Define you validation method before it. An example would be as Joran mentioned
def valid(fn):
return fn.isalpha()

if result.isalpha():
print "the string entered contains only letters !"
I guess ?
a="6"
while not a.isalpha():
a = raw_input("Enter your name:")
print "You entered:",a
if you just wanted to eliminate only words that contained numbers you could do
while any(ltr.isdigit() for ltr in a):

I am trying to create an address book program that will append user input to its appropriate list

I am having trouble getting past writing user input to my list what am I doing wrong here? This is an address book program that I am writing, the assignment is to create parallel lists that will store user input data in the appropriate list using a for or while loop. The program must also have a search function which you can see is at the bottom of the code. My issue that I am having is getting the program to store data within my lists. Unfortunately lists are something that give me lots of trouble I just cant seem to wrap my head around it no matter how much research I have done. The issue im running into is the append.data function when trying to write lastname and firstname to my list of names. what am I doing wrong?
#NICHOLAS SHAFFER
#5/11/2016
#MYADDRESSBOOK
def menu():
index = 0
size = 100
count = 0
answer = raw_input("Are You Creating An Entry [Press 1] \nOr Are You Searching An Entry [Press 2] ")
if answer == "1" :
print ("This is where we create")
append_data(index, size, count)
elif answer == "2" :
print ("this is where we search")
search_database()
name[size]
phone[size]
addresss[size]
# IF we are creating
def append_data(index, size, count):
# collect information
for index in range(0, 100):
optOut = 'no'
while optOut == 'no':
lastname[count] = raw_input("What is the persons last name? ")
firstname[count] = raw_input("What is the persons first name? ")
phone[count] = raw_input("What id the persons phone number? ")
address[count] = raw_input("What is the persons address? ")
count = count + 1
print 'Would you like to create another entry?'
optOut = raw_input('Would you like to create another entry? [ENTER YES OR NO]:')
if optOut == 'yes':
menu()
#create string to print to file
#print temp1
#print (firstname + " " + lastname + ", " + phone + ", " + email + ", " + address)
print listName[index]
print listPhone[index]
print listAddress[index]
print 'file has been added to your addressbook sucessfuly'
menu()
# SEARCHING FOR A RECORD
def search_database():
searchcriteria = raw_input("Enter your search Criteria, name? phone, or address etc ")
print searchcriteria
if searchcriteria == "name":
temp1 = open(listName[lastname, firstname],"r")
print temp1
if searchcriteria == "phone":
temp1 = open(listPhone[0], "r")
print temp1
if searchcriteria == "address":
temp1 = open(listAddress[0], "r")
print temp1
else:
print "sorry you must enter a valid responce, try again."
menu()
for line in temp1:
if searchcriteria in line:
print line
errorMessage()
# USER DID NOT PICK CREATE OR SEARCH
def errorMessage():
print ("Incorrect Answer")
exit()
menu()

Your error message says it all:
line 34, in append_data lastname[count]... NameError: global name 'lastname' is not defined
You'll get this same error if you type lastname[4] in any interpreter -- you've simply never defined a list called lastname, so you can't access items in it. In the short term, you can fix this with a line
lastname = list()
You're going to end up with more troubles though; lastname won't be accessible outside the function where you define it, neither will listName. I'd probably approach that by writing them into a data file/database, or maybe creating a quick class whose members will all have access to self.lastname.

My final append for lists thanks again Noumenon
def append_data(index, size, count):
lastnames = list()
if count < size -1:
lastname = raw_input("What is the persons last name? ")
lastnames.append(lastname)
print lastnames
firstnames = list()
if count < size - 1:
firstname = raw_input("What is the persons first name? ")
firstnames.append(firstname)
print firstnames
phones = list()
if count < size - 1:
phone = raw_input("What id the persons phone number? ")
phones.append(phone)
print phones
addresss = list()
if count < size - 1:
address = raw_input("What is the persons address? ")
addresss.append(address)
print addresss
listName = (lastnames, firstnames)
addressbook =(listName, phones, addresss)
index = index + 1
count = count + 1
print addressbook
optOut = raw_input('Would you like to create another entry? [Enter YES or NO]: ')
if optOut == 'YES':
menu()
print 'file has been added to your addressbook sucessfuly'
menu()

Why are some variables not defined?

This is what I have to do:
Look up and print the student GPA
Add a new student to the class
Change the GPA of a student
Change the expected grade of a student
Print the data of all the students in a tabular format
Quit the program
import student
import pickle
lookup = 1
change = 2
add = 3
delete = 4
QUIT = 0
FILENAME = 'student.dat'
def main():
students_info = load_students()
choice = 0
load_students()
#add(students_info)
change_grade(students_info)
change_GPA(students_info)
#get_menu_choice()
look_up(students_info)
while choice != QUIT:
choice = get_menu_choice()
if choice == lookup:
look_up(students_info)
elif choice == add:
add(students_info)
elif choice == change:
change(students_info)
elif choice == delete:
delete(students_info)
save_students(students_info)
def load_students():
try:
input_file = open(FILENAME, 'rb')
students_dict = pickle.load(input_file)
input_file.close()
except IOError:
students_dict = {}
print(students_dict)
return students_dict
def get_menu_choice():
print()
print('Menu')
print("-------------------")
print('1. Look up ID')
print('2.....')
choice = int(input("Enter your choice:"))
return choice
def look_up(students_info):
ID = input('Enter ID:')
print(student_info.get(ID, "Not found!"))
## try:
## print(students_info[ID])
## except KeyError:
## print("Not found!")
def change_GPA(students_info):
ID = input("ID:")
if ID in students_info:
GPA= float(input("New GPA:"))
students=student.Student(ID,GPA,grade,work)
students_info[ID] = students
print ("This",students_info[ID])
else:
print("Not found!")
def change_grade(students_info):
ID = input("ID:")
if ID in students_info:
New_grade = input("Enter new grade:")
students=student.Student(ID,GPA,grade,work)
students_info[ID] = students
#new_grade = students_info[name]
else:
print("Not found!")
def add(students_info):
name = input("Enter the student name:")
ID= input("Enter student's ID:")
GPA= float(input("Enter GPA:"))
grade= input("Enter student's expected grade:")
work = input("Does the student work part time or full time?")
students=student.Student(name,ID,GPA,grade,work)
print(students_info['ID'])
def save_students(students_info):
output_file = open(FILENAME, 'wb')
pickle.dump(students_info, output_file)
output_file.close()
main()
Whenever I tried to change the GPA or grade it's not defined. How could I change one value from the dictionary studens_info?

As gus42 has commented, the errors you are getting are from the lines:
students=student.Student(ID,GPA,grade,work)
You've not defined grade or work in either of the places you do this (nor GPA in change_grade), so it should not be surprising that you're getting an error.
I think there are two ways to fix the issue:
The simplest way is to change your logic from creating a new Student object to modifying the one that already exists. I don't know exactly what the attribute names are in your Student class, but here's a reasonable guess at a solution:
def change_GPA(students_info):
ID = input("ID:")
if ID in students_info:
GPA= float(input("New GPA:"))
students_info[ID].GPA = GPA # assign new GPA to old student object
else:
print("Not found!")
def change_grade(students_info):
ID = input("ID:")
if ID in students_info:
grade = input("Enter new grade:")
students_info[ID].grade = grade # assign new grade to existing student object
else:
print("Not found!")
The other option is to replace the existing Student object with a new one with some different values. This is close to what your current code, but it only really makes sense if your Student objects are immutable (perhaps because you made the type with namedtuple?). To make it work (where your current code does not), you'll have to load the old values from the old Student object before making the new object:
def change_GPA(students_info):
ID = input("ID:")
if ID in students_info:
new_GPA = float(input("New GPA:"))
old_grade = students_info[ID].grade # load old values
old_work = students_info[ID].work
new_student = students.Student(ID, new_GPA, old_grade, old_work)
students_info[ID] = new_student # replace the old student with a new object
else:
print("Not found!")
def change_grade(students_info):
ID = input("ID:")
if ID in students_info:
new_grade = input("Enter new grade:")
old_GPA = students_info[ID].GPA
old_work = students_info[ID].work
new_student = students.Student(ID, old_GPA, new_grade, old_work)
students_info[ID] = new_student
else:
print("Not found!")

have a raw input in a variable?

For a project I need to have a program ask a contests name, use the name in another question.
The Code below works.
The Main problem is that I need the time entered as a value and saved so I can calculate it later, but print in a line that says time = """"" , doesn't work.
Any suggestions on how to approach this problem?
def main():
print "~*~*~*~*~*~ Timbuktu Archery Contest ~*~*~*~*~*~"
archerList = [] #list
name = raw_input ("Enter contestants first name: ")
s = str(name)
archerList.append(name)
print "Enter time (in milliseconds) for " + s , raw_input (": ")
main()

i think you need to do
t = raw_input ("Enter time (in milliseconds) for %s :" % s)

For raw_input returns a string value,
So x = raw_input() will assign the string of what the user has input to x.
See this for docs of raw_input.
For your archerslist, you may want to use a dictionary instead as then you can access the "time" with the name of the archer.
See here for dictionary documentation
You can use dictionaries like this:
def main():
print "~*~*~*~*~*~ Timbuktu Archery Contest ~*~*~*~*~*~"
archers = {}
while True: # get inputs till user inputs empty string.
name = raw_input ("Enter contestants first name: ")
if name == '':
break
while True: # get input till ttime can be converted to an int.
ttime = raw_input ("Enter time (in milliseconds) for %s :" % name)
try:
ttime = int(ttime)
except ValueError: # error handling
print 'Invalid input, Enter a number'
else:
break
archers[name] = ttime # assign values to the dictionary
return archers # return dictionary value