Python function not running, interpreter not giving any errors

Question

I'm very new to Python and having a problem with a program I'm doing for a class. main() and create_file work, but when it gets to read_file, the interpreter just sits there. The program is running but nothing is happening.

The answer is probably something very simple, but I just can't see it. Thanks in advance for any help.

I'm using IDLE (Python and IDLE v. 3.5.2)

Here's the code:

import random

FILENAME = "randomNumbers.txt"

def create_file(userNum):

    #Create and open the randomNumbers.txt file
    randomOutput = open(FILENAME, 'w')

    #Generate random numbers and write them to the file
    for num in range(userNum):
        num = random.randint(1, 500)
        randomOutput.write(str(num) + '\n')

    #Confirm data written
    print("Data written to file.")

    #Close the file
    randomOutput.close()

def read_file():

    #Open the random number file
    randomInput = open(FILENAME, 'r')

    #Declare variables
    entry = randomInput.readline()
    count = 0
    total = 0

    #Check for eof, read in data, and add it
    while entry != '':
        num = int(entry)
        total += num
        count += 1

    #Print the total and the number of random numbers
    print("The total is:", total)
    print("The number of random numbers generated and added is:", count)

    #Close the file
    randomInput.close()

def main():

    #Get user data
    numGenerate = int(input("Enter the number of random numbers to generate: "))

    #Call create_file function
    create_file(numGenerate)

    #Call read_file function
    read_file()

main()

while entry != '': You never change entry inside the loop, so it will keep looping forever. — Barmar
– Barmar, Commented Oct 6, 2016 at 22:13
Are you sure it's actually running? You defined some functions, but did you ever call them? — sytech
– sytech, Commented Oct 6, 2016 at 22:14
@Barmar You're right - I forgot to put entry = randomInput.readline() in the while loop - thank you! I feel a bit stupid, lol. — NoOne
– NoOne, Commented Oct 6, 2016 at 23:35

Barmar · Accepted Answer · 2016-10-06 22:16:17Z

6

You have an infinite while loop in the function, since entry never changes during the loop.

The Pythonic way to process all the lines in a file is like this:

for entry in randomInput:
    num = int(entry)
    total += num
    count += 1

answered Oct 6, 2016 at 22:16

Barmar

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3 Comments

juanpa.arrivillaga Over a year ago

You can make it even more pythonic by wrapping using a context manager.

NoOne Over a year ago

Thank you! For some reason I thought the while loop would stop when it reached the end of the file.

NoOne Over a year ago

I realize I forgot to put entry = randomInput.readline() inside the while loop. Ugh, I feel stupid.

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