I need to use functions in order to mimic the functions of an ATM machine. The functions I need to define are for deposit, withdraw, balance inquiry and quit. The default amount of money is given from an external file.
#đź”’ Mimicking an ATM in Python
subtle sorrel
rugged iglooBOT
I need to use functions in order to mimic the functions of an ATM machine. The f...
@subtle sorrel
Python help channel opened
subtle sorrel
The code I have rn is this:
f = open("project_read.txt")
def init(self.balance):
self.balance = float(f.read())
def deposit(self.balance, amount):
self.balance += amount
print("Your new balance is: $", self.balance)
def withdraw(self.balance, amount):
if (self.balance - amount) < 0:
print("Insufficient funds.")
else:
self.balance -= amount
if self.balance < 100:
print("Warning! Your balance is currently under $100!")
print("Your new balance is: $", self.balance)
else:
print("Your new balance is: $", self.balance)
def quit(self.balance):
f = open("project.txt")
f.write(self.balance)
print("Thank you for choosing our ATM.")
but im sure there's a lot here that I can clip out, and even after this, i need to be able to probably make a while loop that keeps going until the user inputs something that calls the quit function and stops the program or whatever
im sure i probably dont need some of the "self" parts or whatever bc im not defining a class here
quiet shard
Improper use of self. Need to be a class
subtle sorrel
just making sure
and i wasnt sure whether or not i needed to keep the "amount" variables in the definitions, but i dont see why i wouldnt need them
bc you can define the variable with the call of the function or whatever, iirc
quiet shard
balance is a local variable in a function so not available for reuse
blissful laurel
def deposit(self.balance, amount):
```should be
```py
def deposit(self, amount):
and same for the other
also yeah these should be inside a class
subtle sorrel
the teacher told me they shouldnt be or i dont have to do that
when i sent her an email
blissful laurel
she might've said that you don't have to use a class (idk), but what you have here are methods that belong in a class body
you can't just delete the class ATM: and keep everything else the same
subtle sorrel
and thats probably bc i was confused bc i kept thinking that every function needs to have "self" within the parentheses
when thats probably not the case
but if its not, would it be possible for me to like
get rid of the init function and have the balance be defined outside of the definitions
or do i need to keep the init function
quiet shard
I would start with the while loop first then create the function to support it
subtle sorrel
because i forget whether i do or not
blissful laurel
__init__ is used in a class to initialize a new instance of that class
subtle sorrel
cool
f = open("project_read.txt")
balance = float(f.read())
def deposit(balance, amount):
balance += amount
print("Your new balance is: $", balance)
def withdraw(balance, amount):
if (balance - amount) < 0:
print("Insufficient funds.")
else:
balance -= amount
if balance < 100:
print("Warning! Your balance is currently under $100!")
print("Your new balance is: $", balance)
else:
print("Your new balance is: $", balance)
def quit(balance):
f = open("project.txt")
f.write(balance)
print("Thank you for choosing our ATM.")
does this look any better
quiet shard
OK but now you need to call the functions based on project_read.txt
subtle sorrel
right
that file's just used to give the "account" its initial value, there's only one number in there
and im pretty sure i know how to potentially call the functions, probably would use a while loop
but what i want to do is like
quiet shard
so how do you know what function to call?
subtle sorrel
i want to use a while loop, first off
so the user can go through the list and be asked what they want to do over and over until they enter the option that calls the quit function
but the user will have to input like a number or string in order to get the thing they want
quiet shard
You need to return balance if you want to keep track of it
quiet shard
Yes then you have to structyure you function call to recieve the return value
subtle sorrel
ok, cool
so, like....
f = open("project_read.txt")
balance = float(f.read())
def deposit(balance, amount):
balance += amount
print("Your new balance is: $", balance)
return balance
def withdraw(balance, amount):
if (balance - amount) < 0:
print("Insufficient funds.")
else:
balance -= amount
if balance < 100:
print("Warning! Your balance is currently under $100!")
print("Your new balance is: $", balance)
return balance
else:
print("Your new balance is: $", balance)
return balance
def quit(balance):
f = open("project.txt")
f.write(balance)
print("Thank you for choosing our ATM.")
something more like this, yea?
subtle sorrel
should i put that in a while loop, or where should i put it?
quiet shard
In a while loop
quiet shard
with user imputs
subtle sorrel
an if/else embedded into it
maybe
bc that way, i can run or call the functions with the user's input string or number
so like
if the user inputs 1 it runs the deposit
quiet shard
work on what the imput gives
subtle sorrel
2 for withdraw
quiet shard
what about amount?
subtle sorrel
cant that be calculated within the call itself?
quiet shard
how do you know how much to pass to function?
subtle sorrel
through the user's input, but i thought that like
you could do something like deposit(input())
but i could be very wrong
bc of how the calls/functions are formatted
with the balance being the first value in the parentheses
quiet shard
you need 2 things transaction type and amount how will you get these?
subtle sorrel
transaction type will be obtained through the if/else statement
quiet shard
from input
subtle sorrel
aye, but the if/else statement is dependent on the users input is what im trying to say
thats my bad
quiet shard
so I use an atm I choose what transaction. Then if deposit or withdraw Iam asked for amount. Write code to get this input
quiet shard
give it a try.
subtle sorrel
how i am able to assign the value of amount in the functions with the amount that the user gets
or do i just like
set amount equal to input and that works
quiet shard
write a while True loop to input transaction type then post and we can evaluate
subtle sorrel
gotcha, already on it
also thanks for the help btw
f = open("project_read.txt")
balance = float(f.read())
def deposit(balance, amount):
balance += amount
print("Your new balance is: $", balance)
return balance
def withdraw(balance, amount):
if (balance - amount) < 0:
print("Insufficient funds.")
else:
balance -= amount
if balance < 100:
print("Warning! Your balance is currently under $100!")
print("Your new balance is: $", balance)
return balance
else:
print("Your new balance is: $", balance)
return balance
def quit(balance):
f = open("project.txt")
f.write(balance)
print("Thank you for choosing our ATM.")
functcall = input('Thank you for choosing our ATM! To deposit, please enter 1. To withdraw, enter 2. To print a Balance Inquiry, enter 3. Enter 4 to quit.\n')
while functcall != 4:
if functcall == 1:
elif functcall == 2:
elif functcall == 3:
input needs to be inside the loop
subtle sorrel
for functcall?
quiet shard
yes
subtle sorrel
oh right, i forget you can just set a "while true" loop and it just runs
quiet shard
to exit on 4 - quit you can use break
subtle sorrel
right
f = open("project_read.txt")
balance = float(f.read())
def deposit(balance, amount):
balance += amount
print("Your new balance is: $", balance)
return balance
def withdraw(balance, amount):
if (balance - amount) < 0:
print("Insufficient funds.")
else:
balance -= amount
if balance < 100:
print("Warning! Your balance is currently under $100!")
print("Your new balance is: $", balance)
return balance
else:
print("Your new balance is: $", balance)
return balance
def quit(balance):
f = open("project.txt")
f.write(balance)
print("Thank you for choosing our ATM.")
while True:
functcall = input('Thank you for choosing our ATM! To deposit, please enter 1. To withdraw, enter 2. To print a Balance Inquiry, enter 3. Enter 4 to quit.\n')
while functcall != 4:
if functcall == 1:
elif functcall == 2:
elif functcall == 3:
so more like this
imma throw the else function in there, too, dw
just making sure its correct so far
quiet shard
dont need while functioncall
subtle sorrel
alright
quiet shard
the inner while functioncall would just return to while true
subtle sorrel
right
so then would it be better to reserve the "else" to be if the user enters something other than our specified numbers
quiet shard
sure to tidy up for bad input
subtle sorrel
yea, i just added it in, dw
the functcall wont break immediately once 4 is called btw, because thats what the quit function is for
has to output the account value and the message before breaking
quiet shard
oh right
subtle sorrel
but thats all good, bc we can still break the function once that call is run iirc
we'll also need to close the file, but it'd work if we did that within that elif, right?
quiet shard
Your open file code needs work. Plus you need to change it from string to a float
quiet shard
yes i see it
subtle sorrel
but i couldve missed a little something there, so if i need to change it i can
i just remember that before i structured everything with the functions like you told me, i tried it with if/else statements, which was not what i was supposed to do, but it worked
and i had balance or some other thing equal to float(f.read())
quiet shard
show me what you have for the while True now
subtle sorrel
its more or less unchanged, i havent filled the things in with the calls yet
while True:
functcall = input('Thank you for choosing our ATM! To deposit, please enter 1. To withdraw, enter 2. To print a Balance Inquiry, enter 3. Enter 4 to quit.\n')
if functcall == 1:
elif functcall == 2:
elif functcall == 3:
elif functcall == 4:
else:
so if it is 1 or 2 you need an amount. A nested if is what works here
subtle sorrel
alright
quiet shard
I meant an input to get amount. Not the if
subtle sorrel
right
and then assign the amount within the function with the amount we assigned with input
quiet shard
current_balance = deposit(current_balance, deposit_amount)
subtle sorrel
should i also set the input to float, or does it not matter bc the balance is a float and it'll convert it anyway?
quiet shard
yes float
subtle sorrel
gotcha
ok, this is what i have for that call:
if functcall == 1:
deposit_amount = float(input("Please enter how much you would like to deposit.\n"))
current_balance = deposit(current_balance, deposit_amount)
quiet shard
looks right. now almost the same for a withdraw
subtle sorrel
right
elif functcall == 2:
withdraw_amount = float(input("Please enter the amount you would like to withdraw.\n"))
current_balance = withdraw(current_balance, withdraw)
for 3, all we have to do is print the balance
shit, i didnt make a balance inquiry function
def inquiry(balance):
print("Your balance is: $", balance)
return balance
that should work, yea?
quiet shard
yes
subtle sorrel
and then i wrote
elif functcall == 3:
current_balance = inquiry(current_balance)
will that work?
quiet shard
Should
subtle sorrel
aye
then for the quit call, i have
elif functcall == 4:
current_balance = quit(current_balance)
f.close()
break
quiet shard
I learned a different way of reading?writing to files but you can see if that works
quiet shard
unkown input try again?
subtle sorrel
yeye
more or less
now lemme test this out
oh wait, i should probably have it change the functcall to an integer if we're gonna be using numbers
damn, says current balance isnt defined :/
i called for deposit and entered a number, but thats the error i got
quiet shard
change the variable at the top to current_balance = float(f.read())
subtle sorrel
đź‘Ť
all instances of it? like in the functions and such
or somewhere else
wait im dumb, lmao
i got you, my bad
quiet shard
no leave the balance in the funtions alone they are local variables and get destroyed when function exits
subtle sorrel
aight, looks like its working now
gonna put in a few more things, then we'll see if the quit function branch works
mmm, get an error when i try to run the withdraw function
TypeError: unsupported operand type(s) for -: 'float' and 'function'
quiet shard
post what you have
subtle sorrel
it's an error within the function
f = open("project_read.txt")
current_balance = float(f.read())
def deposit(balance, amount):
balance += amount
print("Your new balance is: $", balance)
return balance
def withdraw(balance, amount):
if (balance - amount) < 0:
print("Insufficient funds.")
else:
balance -= amount
if balance < 100:
print("Warning! Your balance is currently under $100!")
print("Your new balance is: $", balance)
return balance
else:
print("Your new balance is: $", balance)
return balance
def inquiry(balance):
print("Your balance is: $", balance)
return balance
def quit(balance):
f = open("project.txt")
f.write(balance)
print("Thank you for choosing our ATM.")
while True:
functcall = int(input('Thank you for choosing our ATM! To deposit, please enter 1. To withdraw, enter 2. To print a Balance Inquiry, enter 3. Enter 4 to quit.\n'))
if functcall == 1:
deposit_amount = float(input("Please enter how much you would like to deposit.\n"))
current_balance = deposit(current_balance, deposit_amount)
elif functcall == 2:
withdraw_amount = float(input("Please enter the amount you would like to withdraw.\n"))
current_balance = withdraw(current_balance, withdraw)
elif functcall == 3:
current_balance = inquiry(current_balance)
elif functcall == 4:
current_balance = quit(current_balance)
f.close()
break
else:
print("You didn't input any of the listed numbers! Please try again.")
i was trying to see if i could get it to output the warning if i got the balance to be less than 100 but i got that error instead
quiet shard
Thats why you test and test again
subtle sorrel
aye
im just a bit reckless with some of these things, cos i havent had a particularly fun time with the class, lmao
but with all that being said, you have helped a lot and i appreciate your time
i do get an error with the quit function tho, cos it says the directory for the file doesnt exist
but im supposed to be making the file with the code
quiet shard
With any project think of the steps you need to do. You worked on the functions first but maybe look at the while true first next time
quiet shard
I thought that might not work
subtle sorrel
aye
the printing files and such or whatever can be fussy sometimes
we had some issues with it in class, as a matter of fact
but thats the only thing left to fix
quiet shard
read this for the proper way to handle a file. https://www.w3schools.com/python/python_file_open.asp
You need to open the file for r , get data ,then close.
when ready to write open the file for w , put data, then close
subtle sorrel
i gotcha
so i need to throw the r in there next to the filename in the function
and then it should be able to allow for writing once it is called
or am i wrong
quiet shard
yes for the r. but than you are in read mode and you are done reading so f.close()
subtle sorrel
actually, should i change the value from 'f' to 'g' for that function? bc i already have 'f' defined as the value used to open the first file
the one with the initial balance
or does it not matter
quiet shard
When ready to write open in w mode write data then f.close()
it can be f because you closed the read so it is not in use
subtle sorrel
alright, lemme change the code real quick in that case and you can lmk what you think
f = open("project_read.txt")
current_balance = float(f.read())
def deposit(balance, amount):
balance += amount
print("Your new balance is: $", balance)
return balance
def withdraw(balance, amount):
if (balance - amount) < 0:
print("Insufficient funds.")
else:
balance -= amount
if balance < 100:
print("Warning! Your balance is currently under $100!")
print("Your new balance is: $", balance)
return balance
else:
print("Your new balance is: $", balance)
return balance
def inquiry(balance):
print("Your balance is: $", balance)
return balance
def quit(balance):
f = open("project.txt", "r")
f.close()
f.write(balance)
print("Thank you for choosing our ATM.")
while True:
functcall = int(input('Thank you for choosing our ATM! To deposit, please enter 1. To withdraw, enter 2. To print a Balance Inquiry, enter 3. Enter 4 to quit.\n'))
if functcall == 1:
deposit_amount = float(input("Please enter how much you would like to deposit.\n"))
current_balance = deposit(current_balance, deposit_amount)
elif functcall == 2:
withdraw_amount = float(input("Please enter the amount you would like to withdraw.\n"))
current_balance = withdraw(current_balance, withdraw_amount)
elif functcall == 3:
current_balance = inquiry(current_balance)
elif functcall == 4:
current_balance = quit(current_balance)
f.close()
break
else:
print("You didn't input any of the listed numbers! Please try again.")
f = open("project_read".txt", "r")
current_balance = float(f.read())
f.close()
in quit
subtle sorrel
alright
subtle sorrel
are you sure? that text file already exists, the point of the quit function is to make a new txt file that has the new balance
it looks like that would write on the existing file
unless im missing something
quiet shard
Yes this replaces the previous balance
subtle sorrel
thats not what im supposed to do
quiet shard
what are your insturctions
subtle sorrel
The instructions are to take a value from an already existing txt file and set that as the account’s initial balance, have the user input what they want to do (deposit, withdraw, print balance) until they use the quit function, which would create an entirely new text file with a different name that holds the new value
Not replacing the original one
So by the end you should have 2 txt files with different values
When you started with 1
Sorry if that wasn’t as clear before
quiet shard
Then choose a different name for saving the new balance txt file. everything else should be the same
subtle sorrel
the teacher requires it to be named like that
Originally it has my last name in there, but I took that out
at least when I pasted it here
It’s still there in the actual code
quiet shard
a second file has to have a different name
subtle sorrel
I thought it did. Did I not have them named differently? Hold on
yeah, first one is project_read while the next is just project
Is there an error in there?
quiet shard
i dont know I am a sloppy typer where are you seeing one
subtle sorrel
I’m not seeing one
It could just be python being fussy
Cos like, even last class people were having trouble
Shit wouldn’t print or even if a file was printed, python couldn’t find the file
quiet shard
post the code and i can test
subtle sorrel
đź‘Ť
f = open("project_read.txt")
current_balance = float(f.read())
f.close()
def deposit(balance, amount):
balance += amount
print("Your new balance is: $", balance)
return balance
def withdraw(balance, amount):
if (balance - amount) < 0:
print("Insufficient funds.")
else:
balance -= amount
if balance < 100:
print("Warning! Your balance is currently under $100!")
print("Your new balance is: $", balance)
return balance
else:
print("Your new balance is: $", balance)
return balance
def inquiry(balance):
print("Your balance is: $", balance)
return balance
def quit(balance):
f = open("project.txt", "r")
f.close()
f.write(balance)
print("Thank you for choosing our ATM.")
while True:
functcall = int(input('Thank you for choosing our ATM! To deposit, please enter 1. To withdraw, enter 2. To print a Balance Inquiry, enter 3. Enter 4 to quit.\n'))
if functcall == 1:
deposit_amount = float(input("Please enter how much you would like to deposit.\n"))
current_balance = deposit(current_balance, deposit_amount)
elif functcall == 2:
withdraw_amount = float(input("Please enter the amount you would like to withdraw.\n"))
current_balance = withdraw(current_balance, withdraw_amount)
elif functcall == 3:
current_balance = inquiry(current_balance)
elif functcall == 4:
current_balance = quit(current_balance)
f.close()
break
else:
print("You didn't input any of the listed numbers! Please try again.")
Hey @subtle sorrel!
subtle sorrel
you should probably make a project_read txt file first, too
the value we had in the file was 5000, but you can put whatever value you want in there
quiet shard
line 1 add , "r"
subtle sorrel
alright
quiet shard
under def quit make it "w" and get rid of f.close() in the function looks like you close in the while true
subtle sorrel
đź‘Ť
now i get a different error, line 38
TypeError: write() argument must be str, not float
current_balance = quit(current_balance)
so do i just change current_balance to a string?
ah, looks like that might be it
lemme try it
it works :D
thanks for the help, i really appreciate it
quiet shard
ok it was working for me
quiet shard
You are a good student and catch on quick. Nice helping you.
subtle sorrel
i hope so, bc i feel like i havent learned all that much in her class when she's teaching LMAO
much appreciated, though. have a good one
quiet shard
đź‘Ť
rugged iglooBOT
Python help channel closed