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...
Related
No matter how many times I google variations of my question, I cannot seem to find a solution. I am a beginner programmer, trying to build a game that randomly generates events as you progress through the stages. The problem I am running into are return statements, and passing the values between different modules. Each method for each file are inside of classes. They are all static methods, and calling these methods is not my problem. It is transferring the value of the variables. I'm not sure where I am going wrong, whether it is how I am structuring it, or if I just don't understand how these return statements work.
This is the first File I am starting from. Print statements will be filled out after everything functions properly.
def story():
print("---Intro Story Text here--- ... we will need your name, Traveler. What might it be?")
user_prompt = Introduction.PlayerIntroduction
name = user_prompt.player_info(1)
print(f"Welcome {name}!")
print(f"----After name is received, more story... how old might you be, {name}?")
age = user_prompt.player_info(2)
This is the file I am trying to get the values from. File: Introduction, Class: PlayerIntroduction
#staticmethod
def player_info(funct_select):
if funct_select == 1:
name = PlayerIntroduction.get_player_name()
player_name = name
elif funct_select == 2:
age = PlayerIntroduction.get_player_age()
player_age = age
return player_name, player_age
#staticmethod
def get_player_name():
print("\n\n\nWhat is your name?")
players_name = input("Name: ")
while True:
print(f"Your name is {players_name}?")
name_response = input("Yes/No: ")
if name_response == "Yes" or name_response == "yes":
name = "Traveler " + players_name
break
elif name_response == "No" or name_response == "no":
print("Let's fix that.")
PlayerIntroduction.get_player_name()
else:
print("Please respond with 'Yes' or 'No'.")
return name
#staticmethod
def get_player_age():
print("\n\n\nHow old are you?")
age = input("Age: ")
while True:
print(f"Your age is {age}?")
age_response = input("Yes/No: ")
if age_response == "Yes" or age_response == "yes":
break
elif age_response == "No" or age_response == "no":
print("Let's fix that.")
PlayerIntroduction.get_player_age()
else:
print("Please respond with 'Yes' or 'No'.")
return age
I would like to use the values for "name" and "age" throughout multiple modules/multiple methods within my program. But in order to get those values, I need to assign a variable to the function call.. Resulting in prompting the user to re-enter their name/age at later stages in the game. My idea to combat this was in the first method of this module, creating a conditional statement "if 'example' == 1: 'run the name prompt' and elif == 2: run age prompt, thinking the initial run with the arguments defined would run these prompts, store the values into the variables (name, age), and finally pass the values to the new variables that are NOT assigned to the function call (p_name, p_age), avoiding triggering the user prompt over and over. Ultimately, this failed, and as the code sits now I am getting:
UnboundLocalError: local variable 'player_age' referenced before assignment
Why is this? The only instance 'player_age' is called that is reachable at this point is in the return statement, indented in-line with the conditional statement. The code should read (If I understand incorrectly, please explain) from top to bottom, executing in that order. The 'if' condition is met, so it should run that. If I were to define 'player_name' and 'player_age' as null at the top of this method to avoid this error, then every time I would need to reference these values initially entered by the user, they would be re-assigned to 'null', negating everything I am trying to do.
Thank you all for your patience, I tried to explain what I was doing and my thought process the best I could. Any feedback, criticism, and flaws within my code or this post are GREATLY appreciated. Everything helps me become a better programmer!! (:
I am very inexperienced with any programming language. I decided for my first for-fun/leaning project to be creating a calculator to add different durations of time (ex. add the length of several songs to find how long an album is).
So far the user input method is pretty basic, and I'll work to fix that once the basics work, so bear with me on that. The calculator is currently capable of adding two times together and printing the correct answer.
My main problem is creating a functional Continue/Clear user prompt. I have a loop asking if the user wants to continue, clear, or exit. User input works correctly, but I don't know how to actually "continue or clear".
My idea: Upon hitting continue, the previous total will become firstNumber, and the user will only be prompted for the second number (nextNumber) and will be given a new sum and receive the same continue/clear/exit prompt. If the user hits clear, it will start at the very beginning and the user will be prompted for a new firstNumber.
Any help is greatly appreciated.
Below is the code:
import datetime
# holds first entry
print("Enter the first number")
seconds_1 = int(input("Seconds: "))
minutes_1 = int(input("Minutes: "))
hours_1 = int(input("Hours: "))
# holds second entry
print("Enter another number")
seconds_2 = int(input("Seconds: "))
minutes_2 = int(input("Minutes: "))
hours_2 = int(input("Hours: "))
# calculation
duration_1 = datetime.timedelta(hours=hours_1, minutes=minutes_1, seconds=seconds_1)
duration_2 = datetime.timedelta(hours=hours_2, minutes=minutes_2, seconds=seconds_2)
total = duration_1 + duration_2
print(total)
# continue, clear, or exit
contClear = input("Continue: Y | Clear: N | Exit: X: ")
cont = False
while cont == False:
if contClear.upper() == "Y" or contClear.upper() == "YES":
print("Next")
cont = True
elif contClear.upper() == "N" or contClear.upper() == "NO":
print("Cleared")
cont = True
elif contClear.upper() =="X" or contClear.upper() == "EXIT":
print("Exiting")
cont = True
else:
print("Invalid Entry")
contClear = input("Continue: Y | Clear: N | Exit: X: ")
print("DONE")
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.
I am trying to finish off my program my adding a menu that allows the user to select a few options that allow the user to store website names and passwords in lists. But there was a problem as soon as I have appended some website names and passwords into their respective vaults where whenn I try to select an option after appending the website names and passwords, "1" for example is the expected input to call the viewapp() function to see the websites and passwords stored so far. The thing is it takes more than twice to call the viewapp() function, where it rejects the first expected input but accepts the 2nd one strangely. Also when I select the 3rd option for the purpose to call summary(), the whole printed summary would print out twice, which is a similar pattern to the menu only accepting the 2nd expected input. The program is doing what I want except for this annoying bug where selecting those four options makes it ask for input a second time when it's supposed to straight away jump to that function. Help would be appreciated.
appvault = []
passvault = []
def logged():
print("----------------------------------------------------------------------\n")
print("Hello, welcome to the password vault console. ")
modea = input("""Below are the options you can choose from in the password vault console:
##########################################################################\n
1) Find the password for an existing webiste/app
2) Add a new website/app and a new password for it
3) Summary of the password vault
4) Exit
##########################################################################\n
> """).strip()
return modea
def viewapp():
if len(appvault) > 0:
for app in appvault:
print("Here is the website/app you have stored:")
print("- {}\n".format(app))
if len(passvault) > 0 :
for code in passvault:
print("Here is the password you have stored for the website/app: ")
print("- {}\n".format(code))
else:
print("You have no apps or passwords entered yet!")
def addapp():
while True:
validapp = True
while validapp:
new_app = input("Enter the new website/app name: ").strip().lower()
if len(new_app) > 20:
print("Please enter a new website/app name no more than 20 characters: ")
elif len(new_app) < 1:
print("Please enter a valid new website/app name: ")
else:
validapp = False
appvault.append(new_app)
validnewpass = True
while validnewpass:
new_pass = input("Enter a new password to be stored in the passsword vault: ")
if not new_pass.isalnum():
print("Your password for the website/app cannot be null, contain spaces or contain symbols \n")
elif len(new_pass) < 8:
print("Your new password must be at least 8 characters long: ")
elif len(new_pass) > 20:
print("Your new password cannot be over 20 characters long: ")
else:
validnewpass = False
passvault.append(new_pass)
validquit = True
while validquit:
quit = input("\nEnter 'end' to exit or any key to continue to add more website/app names and passwords for them: \n> ")
if quit in ["end", "End", "END"]:
logged()
else:
validquit = False
addapp()
return addapp
def summary():
if len(passvault) > 0:
for passw in passvault:
print("----------------------------------------------------------------------")
print("Here is a summary of the passwords stored in the password vault:\n")
print("The number of passwords stored:", len(passvault))
print("Passwords with the longest characters: ", max(new_pass for (new_pass) in passvault))
print("Passwords with the shortest charactrs: ", min(new_pass for (new_pass) in passvault))
print("----------------------------------------------------------------------")
else:
print("You have no passwords entered yet!")
while True:
chosen_option = logged()
print(chosen_option)
if chosen_option == "1":
viewapp()
elif chosen_option == "2":
addapp()
elif chosen_option == "3":
summary()
elif chosen_option == "4":
break
else:
print("That was not a valid option, please try again: ")
print("Goodbye")
This happens because you call logged() when exiting addapp():
if quit in ["end", "End", "END"]:
logged()
Then, the choice you enter is returned by logged(), and thrown away as it isn't assigned to anything.
You're now back at the end of the previous block in addapp(), and the next instruction is return addapp, that will bring you back to your main loop, where you'll be sent to logged() again by chosen_option = logged()
Note that in return addapp, you return the addapp function itself, which is certainly not what you want to do. So, as you don't need a return value for addapp(), just use return, or nothing at all, Python will automatically return at the end of the function.
So, to solve your problem: directly return when you're done entering sites:
if quit in ["end", "End", "END"]:
return
Note also that you recursively call addapp() from itself when you add more sites.
You should generaly avoid that unless you really want to use some recursive algorithm, and rather use a loop as you did in your main loop. By default, Python limits you to 1000 recursion levels - so you could even crash your app by entering more than 1000 sites in a row ;)
The summary problem is only caused by the unnecessary for loop in summary()
You are nearly there. The issue is in the addapp() function at line 63:
if quit not in ["end", "End", "END"]:
logged()
if you replace
logged()
with
pass
Then everything will work a ok.
You are not handling the result of the logged function here anyway.
You also do not need to process the logged function here. The addapp will exit and the logged function will be called and handled in the while loop the addapp function was called from.
I'm trying to create a menu for my application, the menu has 4 options and each of these options should return with the correct information when the user has entered the chosen value. i keep getting an error with the Elif statements.
I am a newbie so please understand where am coming from.
much appreciation.
when i indent the while ans: i will receive an error says invalid syntax after indenting the elif ans==2.
elif ans==2 <--- this error keeps saying indention block error or syntex invalid when i indent it.
def print_menu(self,car):
print ("1.Search by platenumber")
print ("2.Search by price ")
print ("3.Delete 3")
print ("4.Exit 4")
loop=True
while loop:
print_menu()
ans==input("Please choose from the list")
if ans==1:
print("These are the cars within this platenumber")
return platenumber_
while ans:
if ans==2:
elif ans==2:
print("These are the prices of the cars")
return price_
elif ans==3:
print("Delete the cars ")
return delete_
elif ans==4:
return Exit_
loop=False
else:
raw_input("please choose a correct option")
You have a while loop without a body. Generally speaking, if there is an indentation error message and the error is not on the line mentioned, it's something closely above it.
loop=True
while loop:
print_menu()
ans = int(input("Please choose from the list"))
if ans==1:
print("These are the cars within this platenumber")
# return some valid information about plate numbers
elif ans==2:
print("These are the prices of the cars")
# return some valid information about pricing
elif ans==3:
print("Delete the cars ")
# Perform car deletion action and return
elif ans==4:
# I am assuming this is the exit option? in which case
# return without doing anything
else:
# In this case they have not chosen a valid option. Send
# A message to the user, and do nothing. The while loop will run again.
print("please choose a correct option")
Also, your code is a bit confusing to me. It looks like you're going to return car_ no matter what, which means your loop will only execute once. Also, = is assignment and == is equality. Be careful.