How to run python function as many times as user input + read valid lines?

Question

Hi i have this problem quite long and have no idea how to deal with it. I want to program run sth like this :

user write command in discord with argument (amount)
discord function will call read_coupon function with written argument
read_coupon function will open and read lines (depend of amount) and return it from txt file

atm my code ignore user input and return only first line in kody.txt

@client.command()
 async def kody (ctx, amount):
     await ctx.send(read_coupon(int(amount)))

def read_coupon(amount):
    x_range = range(0,amount,1)
    kody_open = open("kody.txt","r")
    for line_kod in kody_open:
        kody_lista.append(line_kod)
    for x in x_range:
        for element in kody_lista:
            return element

kody.txt
NLZGQEJ32W
NLBH9LBZVP
NLB6DRBZ4Q
NLJ8GWAC8M
NLBH9LBZVP
NLB6DRBZ4Q
NLJ8GWAC8M

Andrew Wei · Accepted Answer · 2021-12-26T17:59:36.420

0

You can do something like this:

def read_coupon(amount):
    kody_open = open("kody.txt","r")
    kody_lista = []
    for line_kod in kody_open:
        kody_lista.append(line_kod)
    kody_open.close()
    result = ''
    for i in range(min(len(kody_lista),amount)):
        result += kody_lista[i]
    return result

You need to remember to close the file in case python fails to automatically close the file. You will also want to add a minimum check between the amount and the list in case the amount specified goes over the length of the list.

Alternatively, you can do something like this with a context manager which will automatically close the file upon exiting the context.

def read_coupon(amount):
    result = ''
    with open("kody.txt","r") as f:
        for line in f:
            result += line
            amount -= 1
            if amount == 0: break
    return result

edited Dec 26 '21 at 17:59

answered Dec 26 '21 at 17:53

Andrew Wei

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Good call, still making some edits. – Andrew Wei Dec 26 '21 at 17:56
First one not working good for me, second is fine. Thanks ! – Michał Majewski Dec 26 '21 at 17:58
That makes sense, the copied code didn't have an instantiation of `kody_lista`. – Andrew Wei Dec 26 '21 at 18:02
How to delete printed coupon from ```kody.txt``` ? i'd like to do this also in this loop. – Michał Majewski Dec 26 '21 at 18:28
You might need to do that separately. There's a few ways to do this, but you can reading the rest of the things in the file and putting it in a list/string. After exiting the context, write that back into the file using a new context manager (the line with the `with`). – Andrew Wei Dec 26 '21 at 18:49

How to run python function as many times as user input + read valid lines?

1 Answers1