我该如何解决这个问题：ValueError invalid literal for int() with base 10: ''? Python

Question

import os
txt_file = 'highscore.txt'
score = total_points

if not os.path.exists(txt_file):
    with open(txt_file, 'w') as f:
        f.write('Score: {score}\n'
                + 'Name: {name}')

with open(txt_file, 'r') as f:
    previous_score = int(f.readline().split()[-1])

# compare the previous score with current score and write the highest score
if previous_score < score:
    with open(txt_file, 'w') as f:
        f.write(f'Score: {score}\n'
                + f'Name: {name}')

I understand that because I have Score: on the line, it isn't coming back as just the score. If I use re.findall I can get just the score but it turns into a list, and I still can't use int(previous_score) < int(score) . How do I go about making this work?

Thank you to the previous commenter, Sachin, who helped me get this far by the way.

edit: I managed to get it with all of your help. Thank you so much!

Answer 1

what's wrong with previous_score = int(f.readline().split()[-1])

Answer 2

In your code you are literally writing "Score: {score}" in the txt_file . You don't substitute {score} with the value of the variable score . You can open that file in an editor and confirm. To do this substitution, add f before each string, ie: your code should begin

with open(txt_file, 'w') as f:
    f.write(f'Score: {score}\n'
        + f'Name: {name}')

Then, to extract the score from previous_score , carefull it is the whole line, you should split the line into words and keep the last element, then convert it to integer: int(previous_score.split()[-1]) .

Answer 3

It sounds like you want to extract an int from a string. For example,

previous_score = 'Score: 150\n'             #Which you read from the file with .readline()
score          = previous_score.split()[-1] #Splits a string into words. Take last item. 
print(int(score))