how would i go about reading a .txt file then ordering the data in descending order

Question

ok so i would like it that when the user wants to check the high scores the output would print the data in descending order keep in mind that there are both names and numbers on the .txt file which is why im finding this so hard. If there is anything else you need please tell me in the

def highscore():
        global line #sets global variable
        for line in open('score.txt'):
            print(line)
    #=================================================================================
    def new_highscores():
        global name, f #sets global variables
        if score >= 1:#if score is equal or more than 1 run code below
            name = input('what is your name? ')
            f = open ('score.txt', 'a') #opens score.txt file and put it into append mode
            f.write (str(name)) #write name on .txt file
            f.write (' - ') #write - on .txt file
            f.write (str(score)) #write score on .txt file
            f.write ('\n') #signifies end of line
            f.close() #closes .txtfile
        if score <= 0: #if score is equal to zero go back to menu 2
            menu2() 

I added this just in case there was a problem in the way i was writing on the file

Answer 1

The easiest thing to do is just maintain the high scores file in a sorted state. That way every time you want to print it out, just go ahead and do it. When you add a score, sort the list again. Here's a version of new_highscores that accomplishes just that:

def new_highscores():
    """"Adds a global variable score to scores.txt after asking for name"""
    # not sure you need name and f as global variables without seeing 
    # the rest of your code. This shouldn't hurt though
    global name, f # sets global variables
    if score >= 1: # if score is equal or more than 1 run code below
        name = input('What is your name? ')

        # here is where you do the part I was talking about:
        # get the lines from the file
        with open('score.txt') as f:
            lines = f.readlines()

        scores = []
        for line in lines:
            name_, score_ = line.split(' - ')
            # turn score_ from a string to a number
            score_ = float(score_)
            # store score_ first so that we are sorting by score_ later
            scores.append((score_, name_))

        # add the data from the user
        scores.append((score, name))
        # sort the scores
        scores.sort(reverse=True)

        # erase the file
        with open('score.txt', 'w') as f:
            # write the new data
            for score_, name_ in scores:
                f.write('{} - {}\n'.format(name_, score_))        

    if score <= 0: # if score is equal to zero go back to menu 2
        menu2()

You'll notice I'm using the with statement. You can learn more about that here, but essentially it works like this:

with open(filename) as file:
    # do stuff with file
# file is **automatically** closed once you get down here. 

Even if you leave the block for another reason (an Exception is thrown, you return from a function early, etc.) Using a with statement is a safer way to deal with files, because you're basically letting Python handle the closing of the file for you. And Python will never forget like a programmer will.

You can read more about split and format here and here

P.S., There is a method called binary search that would be more efficient, but I get the feeling you're just starting so I wanted to keep it simple. Essentially what you would do is search for the location in the file where the new score should be inserted by halving the search area at each point. Then when you write back to the file, only write the stuff that's different (from the new score onward.)