python - 为什么我的程序会被注释干扰？

Question

我们在学校的任务是在代码底部添加程序的测试示例:

#example

"""

<insert example of you running the code>

"""

但是当我这样做的时候，我得到了错误。我从来没有在任何其他代码上得到它，只有在这个代码上？:

C:\Users\David>C:\Users\David\Desktop\IN1900\uke38\qerror.py 1
  File "C:\Users\David\Desktop\IN1900\uke38\qerror.py", line 22
    """
    ^
SyntaxError: (unicode error) 'unicodeescape' codec can't decode bytes in position 24-25: truncated \UXXXXXXXX escape

C:\Users\David>

我的代码如下:

from math import sqrt
import sys

a=float(sys.argv[1])
b=float(sys.argv[2])
c=float(sys.argv[3])
d=(b**2)-(4*a*c)
x1=((-b+sqrt(d))/(2*a))
x2=((-b-sqrt(d))/(2*a))

print(f'The quadratic formula with used values gives two roots {x1:.1f} and {x2:.1f}')

#example
"""
#Fra command prompt:
#C:\Users\David>C:\Users\David\Desktop\IN1900\uke38\quadratic_roots_cml.py 1 0 -1
#The quadratic formula with used values gives two roots 1.0 and -1.0
#(koden funker ikke på et eller annet magisk vis når jeg bruker
"""

Answer 1

您的部分字符串文字被解释为转义的 Unicode 字符。此类转义序列以 \U 开头。最简单的解决方法是在双引号的开头三连字符前放置一个 r。这可以防止对文本进行任何类型的转义处理:

r"""
#Fra command prompt:
#C:\Users\David>C:\Users\David\Desktop\IN1900\uke38\quadratic_roots_cml.py 1 0 -1
#The quadratic formula with used values gives two roots 1.0 and -1.0
#(koden funker ikke på et eller annet magisk vis når jeg bruker
"""

这比添加一堆额外的斜杠要容易得多，而且也不会改变文本的可读性。

这是 Python 3 文档对“原始字符串”的描述:

Both string and bytes literals may optionally be prefixed with aletter 'r' or 'R'; such strings are called raw strings and treatbackslashes as literal characters. As a result, in string literals,'\U' and '\u' escapes in raw strings are not treated specially. Giventhat Python 2.x’s raw unicode literals behave differently than Python3.x’s the 'ur' syntax is not supported.