if(x in y)不能在python文件I/O中工作

Question

我正在创建一个高分数据库,到目前为止有两件事情无效.

1. 如果我输入一个已存在于文件中的名称,它将忽略if语句(在代码中提到)我会对它在哪一行发表评论.

2. 当我输入名称和分数时,它将替换highscores.txt文件中的当前名称和分数.

这是我的档案:

name = str(input("Enter your name: "))
score = str(input("Enter your score: "))


file = open("N:\highscores.txt", "r")
if(name in file):
    print("You have already entered a score.")
    file.close()
else:
    file = open("N:\highscores.txt", "w")
    file.writelines(name + " : " + score + "\n")
    file.close()

此外,当我解决这个问题时,我如何按大小顺序订购它们？例如:1.450 2. 300等

谢谢.

Answer 1

Python文件对象不支持in成员资格测试,不.

将文件读入字典,然后对其进行测试:

with open("N:\highscores.txt", "r") as scoresfile:
    scores = {name.strip(): score.strip() for line in scoresfile if ':' in line for name, score in (line.split(':'),)}

if name in scores:
    print("You have already entered a score.")
else:
    with open("N:\highscores.txt", "a") as scoresfile:
        file.write('{} : {}\n'.format(name, score))

请注意,您需要以附加模式打开文件以添加行; w将首先清除打开的文件.