Python中的二次方程

huangapple
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英文:

Quadratic equation in Python

问题

这是我的代码。有人可以帮忙解决问题吗？在下面的代码中，我做了一切，但它不起作用。

  1. def read_equation(textfile: str) -> str:
  2.     with open(textfile, 'r') as file:
  3.         equation = file.read()
  4.     return equation
  1. def get_coefficients(input_str: str, coef: str) -> int:
  2.     for i in input_str.split():
  3.         if i.endswith(coef):
  4.             try:
  5.                 value = i.replace(coef, "", 1)
  6.                 if not value or value == "+":
  7.                     value = "1"
  8.                 elif value == "-":
  9.                     value = "-1"
  10.                 return int(value)
  11.             except ValueError as err:
  12.                 print(err)
  13.                 raise TypeError(f"其他符号 {coef}，不是整数。")

查找系数

  1. def get_a_b_c(input_str: str) -> tuple:
  2.     a = get_coefficients(input_str, "x^2")
  3.     b = get_coefficients(input_str, "x")
  4.     c = get_coefficients(input_str, "")
  5.     return a, b, c

查找判别式

  1. def solve_quadratic_equation(a: int, b: int, c: int) -> str:
  2.     d = b ** 2 - 4 * a * c
  3.     if d > 0:
  4.         x1 = (-b + d ** 0.5) / (2 * a)
  5.         x2 = (-b - d ** 0.5) / (2 * a) # 找到根
  6.         roots = f"x1 = {x1}\nx2 = {x2}"
  7.     elif d == 0:
  8.         x = -b / (2 * a)
  9.         roots = f"x = {x}"
  10.     else:
  11.         roots = "无根"
  12.     return roots

根写入文件

  1. def write_roots(output: str, textfile: str) -> None:
  2.     with open(textfile, 'a') as file:
  3.         file.write('\n')
  4.         file.write(output)

主函数

  1. def main():
  2.     user_input = read_equation(textfile="equation.txt")
  3.     coefficients = get_a_b_c(user_input)
  4.     roots = solve_quadratic_equation(*coefficients)
  5.     write_roots(output=roots, textfile="equation.txt")
  7. if __name__ == "__main__":
  8.     main()

我尝试获取根并将其写入现有文件，但它不起作用。

英文:

here is my code. Can anybody help to solve the problem? In the code below everything what I made but it doesn't work.

  1.     def read_equation(textfile: str) -> str:
  2.         with open(textfile, 'r') as file:
  3.             equation = file.read()
  4.         return equation
  1.     def get_coefficients(input_str: str, coef: str) -> int:
  2.         for i in input_str.split():
  3.             if i.endswith(coef):
  4.                 try:
  5.                     value = i.replace(coef, "", 1)
  6.                     if not value or value == "+":
  7.                         value = "1"
  8.                     elif value == "-":
  9.                         value == "-1"
  10.                     return int(value)
  11.                 except ValueError as err:
  12.                     print(err)
  13.                     raise TypeError(f"Other symbol {coef}, not an int.")

Finding coefficients

  1.     def get_a_b_c(input_str: str) -> tuple:
  3.         a = get_coefficients(input_str, "x^2")
  4.         b = get_coefficients(input_str, "x")
  5.         c = get_coefficients(input_str, "")
  6.         return a, b, c

finding discriminant

  1.     def solve_quadratic_equation(a: int, b: int, c: int) -> str:
  2.         d = b ** 2 - 4 * a * c
  3.         if d > 0:
  4.             x1 = (-b + d ** 0.5) / (2 * a)
  5.             x2 = (-b - d ** 0.5) / (2 * a) # finding roots
  6.             roots = f"x1 = {x1}\nx2 = {x2}"
  7.         elif d == 0:
  8.             x = -b / (2 * a)
  9.             roots = f"x = {x}"
  10.         else:
  11.             roots = "No roots"
  12.         return roots

roots in file

  1.     def write_roots(output: str, textfile: str) -> None:
  2.         with open(textfile, 'a') as file:
  3.             file.write('\n')
  4.             file.write(output)
  6. main function:
  8.     def main():
  9.         user_input = read_equation(textfile="equation.txt")
  10.         coefficients = get_a_b_c(user_input)
  11.         roots = solve_quadratic_equation(*coefficients)
  12.         write_roots(output=roots, textfile="equation.txt")
  2.     if __name__ == "__main__":
  3.         main()

I tried to get roots and write it in existing file, but it doesn't work

答案1

得分: 0

Here is the translated content:

事实上，你有问题的地方是：

  1. c = get_coefficients(input_str, "")

这一行没有正确地获取常数的系数。

现在，如果你运行你的当前代码：

  1. get_coefficients("1x^2 - 10x + 2 = 0")

你会得到：

  1. ----> 5     c = get_coefficients(input_str, "")
  2.       6     return a, b, c
  4. C:\Users\NAVIGA~1\AppData\Local\Temp/ipykernel_27960/1668498165.py 中的 get_coefficients(input_str, coef) 
  5.      11                 except ValueError as err:
  6.      12                     print(err)
  7. ---> 13                     raise TypeError(f"Other symbol {coef}, not an int.")
  9. TypeError: Other symbol , not an int.

解决方法：

你可以通过在方程周围使用 split(' =') 来获取 c 的系数。

  1. def get_a_b_c(input_str: str) -> tuple:
  3.         a = get_coefficients(input_str, "x^2")
  4.         b = get_coefficients(input_str, "x")
  5.         c = int(input_str.split(' =')[0][-1])  # 从拆分中获取 c
  6.         return a, b, c 
  1. print(get_a_b_c("1x^2 - 10x + 2 = 0"))
  3. #输出
  4. (1, 10, 2)

现在，你可以使用你所有的公式：

  1. def solve_quadratic_equation(a: int, b: int, c: int) -> str:
  2.     d = b ** 2 - 4 * a * c
  3.     if d > 0:
  4.         x1 = (-b + d ** 0.5) / (2 * a)
  5.         x2 = (-b - d ** 0.5) / (2 * a) # 寻找根
  6.         roots = f"x1 = {x1}\nx2 = {x2}"
  7.     elif d == 0:
  8.         x = -b / (2 * a)
  9.         roots = f"x = {x}"
  10.     else:
  11.         roots = "没有根"
  12.     return roots
  14. coefficients = get_a_b_c("1x^2 - 10x + 2 = 0")
  16. roots = solve_quadratic_equation(*coefficients)
  18. print(roots)
  20. #输出
  22. 'x1 = -0.2041684766872809\nx2 = -9.79583152331272'
英文:

Actually, you have problem with :

  1. c = get_coefficients(input_str, "")

this line is not correctly fetching the coefficients for the constant.

Now, if you run your current code with this:

  1. get_coefficients("1x^2 - 10x + 2 = 0")

you will get:

  1. ----> 5     c = get_coefficients(input_str, "")
  2.       6     return a, b, c
  4. C:\Users\NAVIGA~1\AppData\Local\Temp/ipykernel_27960/1668498165.py in get_coefficients(input_str, coef)
  5.      11                 except ValueError as err:
  6.      12                     print(err)
  7. ---> 13                     raise TypeError(f"Other symbol {coef}, not an int.")
  9. TypeError: Other symbol , not an int.

Workaround:

You can get coefficient of c by using split(' =') around the equation.

  1. def get_a_b_c(input_str: str) -> tuple:
  3.         a = get_coefficients(input_str, "x^2")
  4.         b = get_coefficients(input_str, "x")
  5.         c = int(input_str.split(' =')[0][-1])  # getting c from split
  6.         return a, b, c 
  1. print(get_a_b_c("1x^2 - 10x + 2 = 0"))
  3. #output
  4. (1, 10, 2)

Now, you can use all your formulas:

  1. def solve_quadratic_equation(a: int, b: int, c: int) -> str:
  2.     d = b ** 2 - 4 * a * c
  3.     if d > 0:
  4.         x1 = (-b + d ** 0.5) / (2 * a)
  5.         x2 = (-b - d ** 0.5) / (2 * a) # finding roots
  6.         roots = f"x1 = {x1}\nx2 = {x2}"
  7.     elif d == 0:
  8.         x = -b / (2 * a)
  9.         roots = f"x = {x}"
  10.     else:
  11.         roots = "No roots"
  12.     return roots
  14. coefficients = get_a_b_c("1x^2 - 10x + 2 = 0")
  16. roots = solve_quadratic_equation(*coefficients)
  18. print(roots)
  20. #output
  22. 'x1 = -0.2041684766872809\nx2 = -9.79583152331272'

huangapple
  • 本文由 发表于 2023年6月26日 20:51:56
  • 转载请务必保留本文链接：https://go.coder-hub.com/76556872.html
  • equation
  • python
  • quadratic
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