Question 303203 in Json Question posted in
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How to implement a leaderboard dictionary to my program by saving and loading to and from a json file?

I programmed a classic Snake using pygame. i want to save the top 5 scores and when someone beats one of those scores the game overrides the current top records. what would the topfive dictionary look like and how can i make a json file to overwrite the scores and save them. Also when you open the game it will automatically load the leaderboard.

I tried this but i dont know how it works exactly because i never worked with json files before:

#creating a json file for top scores
#making the dictionary
top5 = {
    "1": 0,
    "2": 0,
    "3": 0,
    "4": 0,
    "5": 0
}
 
#serializing json
json_object = json.dumps(top5, indent=5)

#writing to json file
with open('topfive.json', 'w') as outfile:
    outfile.write(json_object)
 
#opening json file
with open('topfive.json', 'r') as openfile:
    json_object = json.load(openfile) #reading from json
Tags:

2

Answers


  1. 0

    When someone beats a high score, you can update the dictionary, by using

    for topscorer in top5.keys():
    if(new_highscore > top5[topscorer]):
        top5[topscorer] = new_highscore
        break

    and then do:

    open('topfive.json', 'w').close()

    to erase previous contents of the file, then do:

    top5_file = open("topfive.json", "w") 
  
json.dump(top5, out_file, indent = 6)
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  2. 0

    Your code should work fine, assuming you have imported json

    if you add some print statements to your code you can see it is working

    import json

# creating a json file for top scores
# making the dictionary
top5 = {"1": 4, "2": 4, "3": 3, "4": 1, "5": 0}

# serializing json
json_object = json.dumps(top5, indent=5)

# writing to json file
with open("topfive.json", "w") as outfile:
    outfile.write(json_object)

# opening json file
with open("topfive.json", "r") as openfile:
    json_object = json.load(openfile)  # reading from json

    print(json_object)
    print(type(json_object))
    print(json_object["1"])

    the output would be

    {'1': 4, '2': 4, '3': 3, '4': 1, '5': 0}
<class 'dict'>
4

    A better implementation

    an alternative and more readable implementation would be to store the scores as an array instead of the string indexes in a dictionary, and whenever the user has a new score you add it to the array sort it and truncate it as follows

    import json


def load_leaderboard():
    try:
        with open("top_five.json", "r") as infile:
            leaderboard = json.load(infile)
    except (FileNotFoundError, KeyError):
        leaderboard = []
    return leaderboard


def update_leaderboard(new_score):
    leaderboard = load_leaderboard()

    leaderboard.append(new_score)

    # Order the leaderboard by score in descending order
    leaderboard.sort(reverse=True)

    # Keep only the top 5 scores
    leaderboard = leaderboard[:5]

    with open("top_five.json", "w") as outfile:
        json.dump(leaderboard, outfile, indent=4)


# Example usage:

update_leaderboard(100)
update_leaderboard(200)
update_leaderboard(120)
update_leaderboard(130)
update_leaderboard(180)

print("Updated Leaderboard:", load_leaderboard())

update_leaderboard(90)  # should not be added to the leaderboard
update_leaderboard(10)  # should not be added to the leaderboard

print("Updated Leaderboard:", load_leaderboard())

update_leaderboard(500)  # should be added to the leaderboard

print("Updated Leaderboard:", load_leaderboard())

    the output would be:

    Updated Leaderboard: [200, 180, 130, 120, 100]
Updated Leaderboard: [200, 180, 130, 120, 100]
Updated Leaderboard: [500, 200, 180, 130, 120]
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