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python - 尝试使用 sort() 对列表进行排序

问题描述

在将另一个文件的内容附加到列表（水果）之后，并且在将其写入 txt 文件“fruit_salad.txt”之前，我正在尝试对列表（水果）进行排序。

我遇到的问题是，一旦我写了“fruit.sort()”，它就无法识别输出。

通过对导致这种情况的列表进行排序，我在做什么？

先感谢您。

- -代码 - -

try:
    f = open("fruit.txt", mode='r', encoding='utf-8')
    fruit = f.readlines()
    print(fruit, "\n")


    f1 = open("more_fruit.txt", mode="r", encoding='utf-8')
    fruit.append(f1.readlines())
    print(fruit)
    # fruit.sort() # WITHOUT THIS LINE IT WORKS FINE
    output = open("fruit_salad.txt", mode='w', encoding='utf-8')

    for line in fruit:
        output.writelines(line)

except (FileNotFoundError, IOError):
    print("File Not Found!!")
finally:
    f.close()
    f1.close()
    output.close()

- 输出 - 

 ['pear\n', 'apple\n', 'orange \n', 'mandarin\n', 'watermelon\n', 
 'pomegranate\n', 'lemon\n', 'pineapple\n'] 

  ['pear\n', 'apple\n', 'orange \n', 'mandarin\n', 'watermelon\n', 'pomegranate\n', 'lemon\n', 'pineapple\n', ['banana\n', 'raspberry\n', 'blueberry\n', 'lime\n', 'blackberry\n', 'cherry\n', 'grape']]

程序“python.exe”以代码 0 (0x0) 退出。

错误输出

在处理上述异常的过程中，又出现了一个异常：

Traceback (most recent call last):
  File "C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\Common7\IDE\Extensions\Microsoft\Python\Core\ptvsd_launcher.py", line 111, in <module>
    vspd.debug(filename, port_num, debug_id, debug_options, run_as)
  File "C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\Common7\IDE\Extensions\Microsoft\Python\Core\Packages\ptvsd\debugger.py", line 36, in debug
    run(address, filename, *args, **kwargs)
  File "C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\Common7\IDE\Extensions\Microsoft\Python\Core\Packages\ptvsd\_main.py", line 47, in run_file
    run(argv, addr, **kwargs)
  File "C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\Common7\IDE\Extensions\Microsoft\Python\Core\Packages\ptvsd\_main.py", line 98, in _run
    _pydevd.main()
  File "C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\Common7\IDE\Extensions\Microsoft\Python\Core\Packages\ptvsd\pydevd\pydevd.py", line 1628, in main
    globals = debugger.run(setup['file'], None, None, is_module)
  File "C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\Common7\IDE\Extensions\Microsoft\Python\Core\Packages\ptvsd\pydevd\pydevd.py", line 1035, in run
    pydev_imports.execfile(file, globals, locals)  # execute the script
  File "C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\Common7\IDE\Extensions\Microsoft\Python\Core\Packages\ptvsd\pydevd\_pydev_imps\_pydev_execfile.py", line 25, in execfile
    exec(compile(contents+"\n", file, 'exec'), glob, loc)
  File "C:\Users\micha\source\repos\PythonFileManagement\PythonFileManagement\PythonFileManagement.py", line 24, in <module>
    output.close()
NameError: name 'output' is not defined

标签： pythonpython-3.x

解决方案

您将列表附加到列表的末尾，如您所见，您得到：

[elem11, elem12, ..., elem1n, [elem21, elem22, ..., elem2m]]（列表中的列表）

您需要使用extend而不是append添加所有元素f1.readlines()

fruit.extend(f1.readlines())

来源：https ://developers.google.com/edu/python/lists

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