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Input from user to print out a certain instance variable in python

I have created a class with programs:
class Program:
def __init__(self,channel,start, end, name, viewers, percentage):
self.channel = channel
self.start = start
self.end = end
self.name = name
self.viewers = viewers
Channel 1, start:16.00 end:17.45 viewers: 100 name: Matinee:The kiss on the cross
Channel 1, start:17.45 end:17.50 viewers: 45 name: The stock market today
Channel 2, start:16.45 end:17.50 viewers: 30 name: News
Channel 4, start:17.25 end:17.50 viewers: 10 name: Home building
Channel 5, start:15.45 end:16.50 viewers: 28 name: Reality
I also have created a nested list with the programs:
[[1,16:00, 17,45, 100, 'Matinee: The kiss on the cross'],[1,17:45, 17,50, 45,'The stock market today'],[2,16:45, 17,50, 30,'News'], [4,17:25, 17,50, 10,'Home building'],[5,15:45, 16,50, 28,'Reality']
Now we want the user to be able to write the name of a program:
News
The result should be:
News 19.45-17.50 has 30 viewers
I thought about how you could incorporate a method to avoid the program from crashing if the input is invalid/ not an instance variable
I have tried this:
Check_input():
print('Enter the name of the desired program:')
while True: #Continue asking for valid input.
try:
name = input('>')
if name == #is an instance?
return name
else:
print('Enter a program that is included in the schedule:') #input out of range
except ValueError:
print('Write a word!') #Word or letter as input
print('Try again')
I wonder if I should separate all the program-names from the nested list and check if the user enters a name in the list as input? (Maybe by creating a for-loop to iterate over?)
I also have a question regarding how to print out the selected program when the user enters the correct name? I understand how to rearrange them into the correct order to create the sentence. However, I don't know how to access the correct program in the "memory"
Do you have any suggestions how to combat the problem?
All help is much appreciated!

I wonder if I should separate all the program-names from the nested list and check if the user enters a name in the list as input? (Maybe by creating a for-loop to iterate over?)
Well if all your programs have a unique name then the easiest approach would probably be to store them in a dictionary instead of a nested list like:
programs = {
"News": Program("2", "16:45", "17:50", "News", "30", "60"),
"Reality": <Initialize Program class object for this program>,
...
}
Then you could just use the get dictionary method (it allows you to return a specific value if the key does not exist) to see if the asked program exists:
name = input('>')
program = programs.get(name, None)
if program:
print(program)
else:
# raise an exception or handle however you prefer
And if your programs don't have a unique name then you will have to iterate over the list. In which case I would probably return a list of all existing objects that have that name. A for loop would work just fine, but I would switch the nested list with a list of Program objects since you already have the class.
I also have a question regarding how to print out the selected program when the user enters the correct name? I understand how to rearrange them into the correct order to create the sentence. However, I don't know how to access the correct program in the "memory" Do you have any suggestions how to combat the problem.
I would say that the most elegant solution is to override the __str__ method of your Program class so that you can just call print(program) and write out the right output. For example:
class Program:
def __init__(self,channel,start, end, name, viewers, percentage):
self.channel = channel
self.start = start
self.end = end
self.name = name
self.viewers = viewers
def __str__(self):
return self.name + " " + self.start + "-" + self.end + " has " + self.viewers + " viewers"
should print out
News 19.45-17.50 has 30 viewers
when you call it like:
program = programs.get(name, None)
if program:
print(program)

How to access a class object and its attributes from user input?

I just started programming and I decided to use Python for my first attempts at coding, and I am now practicing with classes and objects.
I apologize if the question I am about to ask has been asked before, but I can't seem to find answers anywhere, so here it goes.
I have a file that contains a class. Below the full code I have written :
#class file
#class prodotti refers to "register" with products in stock and their prices
class Prodotti(): #class Prodotti() contains products from register and their relative specs
def __init__(self, nome="", #name of product
prezzo=0, #product price
quantità=0,): #stock quantity of product
self.nome=nome
self.prezzo=prezzo
self.quantità=quantità
def newproduct(self): #method appends new product and its specs to the end of this file
name=input("Inserire nuovo prodotto: ")
f=open("cassa3.py", "a")
f.write(name + "=Prodotti(nome='" + name + "', ")
price=input("Inserire prezzo prodotto: ")
f.write("prezzo=" + price + ", quantità=0)\n")
f.close()
def tellprice(self): #method should return price of object
inp=input("Di quale prodotto vuoi conoscere il prezzo? ") #asks user which product they want to know the price of
if inp=Prodotti():
print(inp.prezzo)
#class objects
#user can insert new products that are saved below
tortino=Prodotti(nome="Tortino al cioccolato", prezzo=3.4, quantità=0)
muffincioccolato =Prodotti(nome="Muffin al cioccolato", prezzo=1.8, quantità=0)
cupcake=Prodotti(nome='cupcake', prezzo=2, quantità=0)
In another file, saved in the same directory, I have the main program:
from cassa3 import Prodotti #file cassa3.py in same directory as this file
if __name__=="__main__":
P=Prodotti()
P.tellprice()
As you may tell from the code above, what I want method tellprice() to do is to ask the user what product they want to know the price of.
However, I just don't know how to make the user input correspond to a class object, so that I can access its attributes.
Can someone explain how i could manage to do that?
Thanks in advance.

Before you will be able to solve this issue, you will need to fix the design problem you have.
Your comment says # class Prodotti() contains products from register and their relative specs but it is not quite true. This class contains a single product with its name, price and quantity.
You will need to define another class (perhaps Register) that will actually store a list (or dictionary if product names are unique for efficient lookup, or whatever) of products (instances of Prodotti).
The tellprice method currently makes no sense. It simply creates a new instance of Prodotti and the if condition will never be True.
Also, it is highly suggested to use English names in code.
Consider the below example as a general guide:
class Product:
def __init__(self, name, price, quantity):
self.name = name
self.price = price
self.quantity = quantity
# (... some other methods ... )
class Register:
def __init__(self, products):
# this will store the products in a dictionary with products names as keys
# and Product instances as values for an efficient look up by tell_price
self.products = {product.name: product for product in products}
def tell_price(self):
name = input('Which product would you like to know the price of?')
# this will raise KeyError if user inputs a non-existing product name
# and should be caught, or use .get(...) instead
return self.products[name].price
apple = Product('apple', 1, 10)
banana = Product('banana', 2, 2)
register = Register([apple, banana])
print(register.tell_price())
# Which product would you like to know the price of?
>> apple
# 1

I wouldn't make your tellprice include user input.
def tellprice(self): #method should return price of object
return self.price
Then in main (this is significantly simplified):
inp = input("Di quale prodotto vuoi conoscere il prezzo? ")
print(inp.tellprice)
Obviously this assumes they put in the correct product name, so some way of indicating to the user that they're incorrect might be useful

Writing dictionary output to file - Python

I have a small program to track monthly balances. This worked fine as is, and then I added in the section to write to a .txt file at the bottom. I did some searching but can't figure out a way to make it work. Basically I want to keep appending to this test.txt file. Every time I enter a new month/account/balance I want that appended to the file.
The alternative is to append to the test.txt file after 'exit', so it doesn't do it every loop. Not sure which way is more efficient
***EDIT****
This updated code now creates test.txt file but the file is blank after each loop
Secondary question - I have heard this would be better off using a Class for this, but I haven't any idea how that would look. If someone wants to demonstrate that would be awesome. This isn't homework, this is strictly learning on my own time.
Any ideas? Thanks
# create program to track monthly account balances
savings = []
def add_accounts(date, account, balance):
savings.append({'date': date, 'account': account, 'balance':
balance})
def print_accounts():
print(savings)
while True:
date = input('Enter the date, type exit to exit program: ')
if date == 'exit':
break
account = input('Enter the account: ')
balance = int(input('Enter the balance: '))
add_accounts(date, account, balance)
print_accounts()
with open('test.txt', 'a') as f:
for row in savings():
print (row)
f.write(str(savings[-1]))
file.close()

The problem with your original code is that print_accounts() doesn't return anything, yet you attempt to perform operations on its (nonexistent) return value.
Here is a version of your program made using classes, and with a few corrections:
class Account:
def __init__(self, id, date, balance):
self.id = id
self.date = date
self.balance = balance
def getString(self):
return self.id + "," + self.date + "," + str(self.balance)
savings = []
def add_account(date, account, balance):
savings.append(Account(date, account, balance))
def print_accounts():
for account in savings:
print(account.getString())
while True:
date = input("Enter the date, type exit to exit program: ")
if date.lower() == "exit":
break
else:
account = input('Enter the account: ')
balance = int(input('Enter the balance: '))
add_account(date, account, balance)
print_accounts()
with open("test.txt", "w") as file:
for account in savings:
file.write(account.getString() + "\n")
Some explanation regarding the class: The Account class has 3 fields: id, date, and balance. These fields are defined in the constructor (__init__()). The class also has a method, getString(), which I use to get the string representation of each instance.
Over all, the following changes have been made:
Create an Account class, which serves as the template for the object which holds the data of each account.
Use a loop to print accounts and write them to the file.
Turn date into lowercase before checking to see if it is equal to "exit". This is a minor change but a good habit to have.
Removed f.close(), as it is unnecessary when using a with open() statement.
Created a custom string representation of each instance of Account, consistent with what you would otherwise get.
That last one is achieved via defining the getString method in the account class. There is nothing special about it, it is merely what we use to get the string representation.
A better but quite more advanced way to achieve that is by overriding the __str__ and __repr__ methods of the base object. These are essentially hidden functions that every class has, but which python defines for us. The purpose of these two specific ones is to give string representations of objects. The default code for them doesn't produce anything meaningful:
<__main__.Account object at 0x0000000003D79A58>
However, by overriding them, we can use str() on instances of Account, and we will get a string representation in the exact format we want. The modified class will look like so:
class Account:
def __init__(self, id, date, balance):
self.id = id
self.date = date
self.balance = balance
def __repr__(self):
return self.id + "," + self.date + "," + str(self.balance)
def __str__(self):
return self.__repr__()
This also eliminates the need to loop through savings when writing to the file:
with open("test.txt", "w") as file:
for account in savings:
file.write(account.getString() + "\n")
Turns into:
with open("test.txt", "w") as file:
file.write(str(savings))
This wouldn't have worked before, as str() would have given us the gibberish data you saw earlier. However, now that we have overridden the methods, it works just fine.

Try this code (use -1 to exit):
savings = []
def add_accounts(date, account, balance):
savings.append({'date': date, 'account': account, 'balance':
balance})
def print_accounts():
print(savings)
while True:
date = input('Enter the date, type exit to exit program: ')
if date == -1:
break
account = input('Enter the account: ')
balance = int(input('Enter the balance: '))
add_accounts(date, account, balance)
print_accounts()
with open('test.txt', 'a') as f:
for row in savings:
print (row)
f.write(str(savings[-1]))
f.close()

Searching text file for a words not working and not throwing any errors

Im trying to search a text file i have for an employees name and it doesn't seem to working but it also isn't throwing any errors. Whenever i search for a word in this file it gets inside the get_the_info function but never reaches the for loop it seems. Im assuming this because ive used print statements to try and figure out where the problem is. Im new to programming but i assume that is common convention to figure out some issues? Anyway heres the code:
import os
import sys
class find_employee:
def __init__(self):
self.get_the_info()
def get_the_info(self):
print "inside get info funct"
self.naples_empschedule = open("schedule.txt","r+")
self.read_schedule = self.naples_empschedule.readlines()
self.name = raw_input(" Enter your first and last name please ")
for line in self.naples_empschedule:
print " now inside for loop"
self.values = aline.split()
if self.name in line:
print ("Name:", self.values[0,1],"\n", "Position:", self.values[3],"\n", "Total Hours:", self.values[11])
else:
print ("You dont work here")
find_employee()

You're mixing classes and functions. Try this instead:
class EmployeeFinder(object):
def __init__(self, path_to_schedule, name=None):
self.name = name or raw_input("Enter your first and last name please: ")
self.path_to_schedule = path_to_schedule
def get_the_info(self):
with open(path_to_schedule, "r") as schedule_file:
for line in schedule_file:
values = line.split()
if self.name in line:
print("Name: " + values[0:1] + "\n" + \
"Position: " + self.values[3] + "\n" \
"Total Hours: ", self.values[11])
# note that this still won't work because values[0:1]
# will return a list, not a string. You might need
# ' '.join(values[0:1]).
else:
print("You don't work here")
employeefinder = EmployeeFinder("path/to/schedule/file", "Adam Smith")
employeefinder.get_the_info()
However it looks like you'd probably be better off with a function, rather than trying to force objects on this. Functional programming is NOT a bad thing.
def find_employee(path_to_schedule, name):
with open(path_to_schedule, "r") as schedule_file:
for line in schedule_file:
if name in line:
values = line.split()
new_name = ' '.join(values[0:1]) # I'm guessing at your intent
position = values[3]
hours = values[11]
print("Name: {}\nPosition: {}\nTotal Hours: {}".format(
new_name, position, hours))
(my last example uses string formatting which is a much better solution than string concatenation)

self.values[0,1]
Here you are trying to index a list with a tuple (0,1) which throws an error. Instead use
self.values[0]
or
self.values[1]
depending on which item you want from the list.

I think your for line in self.naples_empschedule:
should be for line in self.read_schedule:.

Python input Job Code

I'm Code doesn't seem to work, I am trying to get input of a job, category, and salary, and store the input
class Jobs:
def GetJob(self):
name = raw_input('Enter a Job Title: ')
category = raw_input('Enter what Category that Job is: ')
salary = raw_input('Enter the salary of that Job: ')
print name,category, salary
def __init__(self,name,category,salary):
self.name = Jobs.GetJob(name)
self.category = Jobs.GetJob(category)
self.salary = Jobs.GetJob(salary)
GetJob = Jobs()
print GetJob

Your code is totally out of good OOP practices, and the first part eandersson's answer too…
A class has for role to store values, get/set them and return (or apply) transformations to its encapsulated values. What you tried to achieve is totally nonsense: you're calling the GetJob method of the Jobs class inside another method. It could work if you would have written:
def __init__(self,name…):
self.name = Jobs.GetJob(self, name)
…
But that would be a wrong way to design your program. You'd better stick your class to hold your values and making it good at that, and make another function that helps populate your class:
class Jobs:
def __init__(self, name, category, salary):
self.name = name
self.category = category
self.salary = salary
def __repr__(self):
return "Jobs<%s,%s,%s>" % (self.name, self.category, self.salary)
def GetJob():
name = raw_input('Enter a Job Title: ')
category = raw_input('Enter what Category that Job is: ')
salary = raw_input('Enter the salary of that Job: ')
return Jobs(name, category, salary)
print GetJob()
I do not agree with eandersson's approach because it deceives the purpose of the constructor, by directly calling the GetJob method. Then GetJob is not useful. And one would want to be able to use the Job class without always having the raw inputs at construction. EDIT: valid only as a comment on the first part of his answer.
And finally, I think that you really misunderstands a lot about programming. You should better read thoroughly a python course like the ones on http://wiki.python.org/moin/BeginnersGuide/NonProgrammers, because there's really a lot of concepts you ignored to be able to write something like that.
go have a look at:
http://hetland.org/writing/instant-hacking.html
http://www.learnpython.org/
http://cscircles.cemc.uwaterloo.ca/
http://learnpythonthehardway.org/book/