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.

Python 3.x input variable

I want to get user input of a code that has to be 11 numbers long and must not contain any characters. Otherwise the question to enter will be repeated.
code=input("Please enter your code ")
while len((code)) !=11: #here should be something to nullify strings inout :)
code = input("Please enter your code and in numbers only ")
There is definitely a better solution for this, just can't think of any.

This might be what you're after
def validate(s):
for char in s: #iterate through string
if not char.isdigit(): # checks if character is not a number
return False # if it's not a number then return False
return True # if the string passes with no issues return True
def enter_code():
while True: #Will keep running until break is reached
code = input("Please enter your code: ") #get user input
# if the length of input and it passes the validate then print 'Your code is valid'
if len(code) == 11 and validate(code):
print('Your code is valid')
break #break out of loop if valid
# if code fails test then print 'Your code is invalid' and return to start of while loop
print('Your code is invalid')
if __name__ == '__main__':
enter_code()

Continuous results from a single function call

I am extremely new to Python, and to programming in general, so I decided to write some basic code to help me learn the ins and outs of it. I decided to try making a database editor, and have developed the following code:
name = []
rank = []
age = []
cmd = input("Please enter a command: ")
def recall(item): #Prints all of the information for an individual when given his/her name
if item in name:
index = name.index(item) #Finds the position of the given name
print(name[index] + ", " + rank[index] + ", " + age[index]) #prints the element of every list with the position of the name used as input
else:
print("Invalid input. Please enter a valid input.")
def operation(cmd):
while cmd != "end":
if cmd == "recall":
print(name)
item = input("Please enter an input: ")
recall(item)
elif cmd == "add":
new_name = input("Please enter a new name: ")
name.append(new_name)
new_rank = input("Please enter a new rank: ")
rank.append(new_rank)
new_age = input("Please input new age: ")
age.append(new_age)
recall(new_name)
else:
print("Please input a valid command.")
else:
input("Press enter to quit.")
operation(cmd)
I want to be able to call operation(cmd), and from it be able to call as many functions/perform as many actions as I want. Unfortunately, it just infinitely prints one of the outcomes instead of letting me put in multiple commands.
How can I change this function so that I can call operation(cmd) once, and call the other functions repeatedly? Or is there a better way to go about doing this? Please keep in mind I am a beginner and just trying to learn, not a developer.

Take a look at your code:
while cmd != "end":
if cmd == "recall":
If you call operation with anything than "end", "recall" or "add", the condition within while is True, the next if is also True, but the subsequent ifs are false. Therefore, the function executes the following block
else:
print("Please input a valid command.")
and the while loop continues to its next lap. Since cmd hasn't changed, the same process continues over and over again.

You have not put anything in your code to show where operator_1, operator_2, and operator_3 come from, though you have hinted that operator_3 comes from the commandline.
You need to have some code to get the next value for "operator_3". This might be from a list of parameters to function_3, in which case you would get:
def function_3(operator_3):
for loopvariable in operator_3:
if loopvariable == some_value_1:
#(and so forth, then:)
function_3(["this","that","something","something else"])
Or, you might get it from input (by default, the keyboard):
def function_3():
read_from_keyboard=raw_input("First command:")
while (read_from_keyboard != "end"):
if read_from_keyboard == some_value_1:
#(and so forth, then at the end of your while loop, read the next line)
read_from_keyboard = raw_input("Next command:")

The problem is you only check operator_3 once in function_3, the second time you ask the user for an operator, you don't store its value, which is why its only running with one condition.
def function_3(operator_3):
while operator_3 != "end":
if operator_3 == some_value_1
function_1(operator_1)
elif operator_3 == some_value_2
function_2
else:
print("Enter valid operator.") # Here, the value of the input is lost
The logic you are trying to implement is the following:
Ask the user for some input.
Call function_3 with this input.
If the input is not end, run either function_1 or function_2.
Start again from step 1
However, you are missing #4 above, where you are trying to restart the loop again.
To fix this, make sure you store the value entered by the user when you prompt them for an operator. To do that, use the input function if you are using Python3, or raw_input if you are using Python2. These functions prompt the user for some input and then return that input to your program:
def function_3(operator_3):
while operator_3 != 'end':
if operator_3 == some_value_1:
function_1(operator_3)
elif operator_3 == some_value_2:
function_2(operator_3)
else:
operator_3 = input('Enter valid operator: ')
operator_3 = input('Enter operator or "end" to quit: ')

looks like you are trying to get input from the user, but you never implemented it in function_3...
def function_3(from_user):
while (from_user != "end"):
from_user = raw_input("enter a command: ")
if from_user == some_value_1:
# etc...

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

How to check for white space input in python

I'm very new to programming and python. I'm writing a script and I want to exit the script if the customer type a white space.
questions is how do I do it right?
This is my attempt but I think is wrong
For example
userType = raw_input('Please enter the phrase to look: ')
userType = userType.strip()
line = inf.readline()
while (userType == raw_input)
print "userType\n"
if (userType == "")
print "invalid entry, the program will terminate"
# some code to close the app

I know this is old, but this may help someone in the future. I figured out how to do this with regex. Here is my code:
import re
command = raw_input("Enter command :")
if re.search(r'[\s]', command):
print "No spaces please."
else:
print "Do your thing!"

The program you provided is not a valid python program. Because you are a beginner some small changes to you program. This should run and does what I understood what it should be.
This is only a starting point: the structure is not clear and you have to change things as you need them.
userType = raw_input('Please enter the phrase to look: ')
userType = userType.strip()
#line = inf.readline() <-- never used??
while True:
userType = raw_input()
print("userType [%s]" % userType)
if userType.isspace():
print "invalid entry, the program will terminate"
# some code to close the app
break

You could strip all whitespaces in your input and check if anything is left.
import string
userType = raw_input('Please enter the phrase to look: ')
if not userType.translate(string.maketrans('',''),string.whitespace).strip():
# proceed with your program
# Your userType is unchanged.
else:
# just whitespace, you could exit.

After applying strip to remove whitespace, use this instead:
if not len(userType):
# do something with userType
else:
# nothing was entered