Function running differently in separate instances-python

Question

I have written this program that takes a file called Sonnets and firstly, changes all the roman numerals in the sonnets to numbers, copies that to a new file, then asks the user for number input and shows them the sonnet corresponding to their number (if between 1 and 7).

For numbers outside 1 and 7, I would display appropriate error messages, giving specific directions on what they inputted and what they need to input again.

I wrote all of my functions separately, and everything runs when I put them together EXCEPT for the "except" part in function serve_poem(). It gave me the correct error message when I ran the function separately, however, now it just gives me the automatic error message instead of the specific message I encoded.

I posted my whole code below, because I figure that something in one of the other functions is messing with it(???) because it ran fine on its own.

def change_romans_to_numbers(s):
    if   s == "I.":     
        return("1.")
    elif s == "II.":    
       return("2.")
    elif s == "III.":   
        return("3.")
    elif s == "IV.":   
        return("4.")
    elif s == "V.":    
        return("5.")
    elif s == "VI.":    
        return("6.")
    elif s == "VII.":   
        return("7.")
    else:               
        return s

def serve_poem():
    sonnet=open(r"C:\Users\Emily\Documents\sonnets.txt", "r")
    x=int(input("Please enter a number 1-7:"))
    s=sonnet.readlines()
    s=list(s)
    try:
        if x==1:
            up=int(2+14*(x-1))
            lower=int(2+14*(x-1)+14)
            for i in range (up,lower):
                print(s[i])
        if 2<=x<=7:
            up=int((2+14*(1-1))+(19*(x-1)))
            lower=int((2+14*(1-1)+14)+(19*(x-1)))
            for i in range (up,lower):
                print(s[i])
        if x<0:
            print("You entered a negative number. Please enter a number between 1 and 7:")
            serve_poem()
        if x==0:
            print("You entered 0. Please enter a number between 1 and 7:")
            serve_poem()
        if x>7:
            print("You entered a number greater than 7. Please enter a number between 1 and 7:")
            serve_poem()
    except ValueError:
        print("Error: Value Error. You did not enter a number at all! Please re-enter a number:")
        serve_poem()

def writing_romans_to_numbers():        
    sonnet=open(r"C:\Users\Emily\Documents\sonnets.txt", "r")
    sonnet_fixed=open(r"C:\Users\Emily\Documents\sonnets-fixed.txt", "w")
    for line in sonnet:
        new=change_romans_to_numbers(line.strip())
        sonnet_fixed.write(new + '\n')

def main():
    writing_romans_to_numbers()
    serve_poem()

main()

Here is my error message (if user inputs q):

File "C:/Users/Emily/.spyder2-py3/temp.py", line 28, in serve_poem
x=int(input("Please enter a number 1-7:"))

ValueError: invalid literal for int() with base 10: 'q'

What do you mean by *the automatic error message*? Can you please include the **full** output of that message in your question? — Martijn Pieters, Mar 15 '15 at 09:06
You probably should read all of [Asking the user for input until they give a valid response](http://stackoverflow.com/q/23294658), it'll teach you a lot about how to take end-user input, including why you shouldn't recursion to handle repetition. — Martijn Pieters, Mar 15 '15 at 09:08
You should put `x=int(input("Please enter a number 1-7:"))` inside the `try` block, just before line `if x == 1`. Also, because the `serve_poem` function is recursive, the sonnets file is opened multiple times and not closed, which is bad. — Yegor Roganov, Mar 15 '15 at 09:12
Thanks Martijn- that post answered my question. Apologize for the repeat — Megan, Mar 15 '15 at 09:13

score 0 · Answer 1 · answered Mar 15 '15 at 09:11

Your problem is that you aren't wrapping this line in the try...except block:

    x=int(input("Please enter a number 1-7:"))

This line will raise an exception if given non-numeric input, but this exception will not handled by your try...except block. You would only need to put that one line in a try...except block, if that line passes it will be guaranteed to be numeric input, so your comparisons should work.

However, as Martjin said, that isn't the best approach.

Function running differently in separate instances-python

1 Answers1