python - 如何在 python 中将文件行转换为 float/int

Question

每当我尝试运行这段代码时:

    #Open file
    f = open("i.txt", "r")
    line = 1

    #Detect start point
    def findstart( x ):
        length = 0
        epsilon = 7
        a = 3
        line_value = int(f.readline(x))
        if line_value == a:
            length = length + 1
            x = x + 1
            findend(x)
        elif line_value == epsilon:
            x = x + 2
            findstart(x)
        else:
            x = x + 1
            findstart(x)

    #Detect end point
    def findend(x):
        line_value = int(f.readline(x))
        if line_value == a:
            length = length + 1
            return ("Accept", length)
        elif line_value == epsilon:
            x = x + 2
            length = length + 2
            findend(x)
        else:
            x = x + 1
            length = length + 1
            findend(x)

    findstart(line)

我得到这个错误代码:

    Traceback (most recent call last):
  File "C:\Users\Brandon\Desktop\DetectSequences.py", line 39, in <module>
    findstart(line)
  File "C:\Users\Brandon\Desktop\DetectSequences.py", line 16, in findstart
    findend(x)
  File "C:\Users\Brandon\Desktop\DetectSequences.py", line 26, in findend
    line_value = int(f.readline(x))
    ValueError: invalid literal for int() with base 10: ''

谁能帮我找出问题所在？在我看来，它正在尝试读取一个空单元格，但我不知道为什么会这样。我正在扫描的文件目前只有两行，每行都是“3”，所以它应该输出成功，但我无法克服这个错误。

Answer 1

我不确定您的代码，但错误消息表明您的文件中有一个空行，您正在尝试将其转换为 int。例如，很多文本文件最后都有一个空行。

我建议在转换之前先检查您的线路:

line = ...
line = line.strip() # strip whitespace
if line: # only go on if the line was not blank
    line_value = int(line)