如何 append 文本（.txt）文件中每一行的行號？

Question

我創建了兩個函數，一個用於計算文本文件中的行數 (count_lines)，第二個 (write_numbers) 用於 append 從 0 開始到文本文件每一行的行號。 我的計數線 function 工作正常，但寫入數字 function 給我一個錯誤。 引發了 TypeError，但我在代碼中將數字轉換為字符串。 不知道這里發生了什么。 每個 function 的代碼和規格如下。

    Error:
    >>> funcs.write_numbers('files/writefile1.txt',5)
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
      File "/home/codio/workspace/exercise1/funcs.py", line 45, in write_numbers
        n = count_lines(file)
      File "/home/codio/workspace/exercise1/funcs.py", line 19, in count_lines
        file = open(filepath)
    TypeError: expected str, bytes or os.PathLike object, not _io.TextIOWrapper

    Text File:

    This file is used to test count_lines
    It has 6 lines
    3
    4
    5
    6

def count_lines(filepath):
    """
    Returns the number of lines in the given file.
    
    Lines are separated by the '\n' character, which is standard for Unix files.
    
    Parameter filepath: The file to be read
    Precondition: filepath is a string with the FULL PATH to a text file
    """
    # HINT: Remember, you can use a file in a for-loop
    file = open(filepath)
    line_count = 0 
    for line in file:
        if line != '/n':
            line_count += 1
    return line_count
            

def write_numbers(filepath,n):
    """
    Writes the numbers 0..n-1 to a file.
    
    Each number is on a line by itself.  So the first line of the file is 0,
    the second line is 1, and so on. Lines are separated by the '\n' character, 
    which is standard for Unix files.  The last line (the one with the number
    n-1) should NOT end in '\n'
    
    Parameter filepath: The file to be written
    Precondition: filepath is a string with the FULL PATH to a text file
    
    Parameter n: The number of lines to write
    Precondition: n is an int > 0.
    """
    # HINT: You can only write strings to a file, so convert the numbers first
    file = open(filepath,'a')    
    n = count_lines(file)
    i = 0
    for line in file:
        if line != '/n':
            i += 1
            file.write(str(i))
            if i == n-1:
                break
    print(file)

Answer 1

問題是您試圖打開文件兩次：

file = open(filepath,'a')    
n = count_lines(file)

然后，在count_lines ：

def count_lines(filepath):
    ...
    file = open(filepath)
    ...

您正在嘗試打開一個文件，其path參數是文件 object 而不是路徑！