--- id: 5e44412c903586ffb414c94c title: 算术格式化 challengeType: 23 forumTopicId: 462359 dashedName: arithmetic-formatter --- # --description-- 小学生经常把算术题垂直排列，这样更容易解决。 例如，“235 + 52” 变成： ```py 235 + 52 ----- ``` Finish the `arithmetic_arranger` function that receives a list of strings which are arithmetic problems, and returns the problems arranged vertically and side-by-side. 该函数应该接受可选的第二个参数。 当第二个参数设置为 `True` 时，应显示答案。 ## 示例 函数调用： ```py arithmetic_arranger(["32 + 698", "3801 - 2", "45 + 43", "123 + 49"]) ``` 输出: ```py 32 3801 45 123 + 698 - 2 + 43 + 49 ----- ------ ---- ----- ``` 函数调用： ```py arithmetic_arranger(["32 + 8", "1 - 3801", "9999 + 9999", "523 - 49"], True) ``` 输出: ```py 32 1 9999 523 + 8 - 3801 + 9999 - 49 ---- ------ ------ ----- 40 -3800 19998 474 ``` ## 规则 如果提供的问题格式正确，该函数将返回正确的转换，否则，它将 **返回** 一个 **字符串** 来描述对用户有意义的错误。 - 会返回错误的情况： - 如果提供给函数的**问题过多**。 The limit is **five**, anything more will return: `'Error: Too many problems.'` - 函数可以接受的运算符是**加法**和**减法**。 乘法和除法将返回错误。 本要点中未提及的其他运算符将不需要进行测试。 The error returned will be: `"Error: Operator must be '+' or '-'."` - 每个数字（操作数）应该只包含数字。 Otherwise, the function will return: `'Error: Numbers must only contain digits.'` - 每个操作数（即运算符每一侧的数字）的宽度最多为四位数字。 Otherwise, the error string returned will be: `'Error: Numbers cannot be more than four digits.'` - 如果用户提供了正确格式的问题，返回的转换将遵循以下规则： - 操作符和两个操作数中最长的一个之间应该有一个空格，操作符将与第二个操作数在同一行，两个操作数的顺序与提供的相同（第一个是上面的，第二个是下面的）。 - 数字应该右对齐。 - 每个问题之间应该有四个空格。 - 每个问题的底部都应该有破折号。 破折号应该单独沿着每个问题的整个长度延伸。 （上面的例子展示了这应该是什么样子。） # --hints-- `arithmetic_arranger(["3801 - 2", "123 + 49"])` should return `3801 123\n- 2 + 49\n------ -----`. ```js ({ test: () => { runPython(` from unittest import TestCase TestCase().assertEqual(arithmetic_arranger(["3801 - 2", "123 + 49"]), ' 3801 123\\n- 2 + 49\\n------ -----')`); } }) ``` `arithmetic_arranger(["1 + 2", "1 - 9380"])` should return `1 1\n+ 2 - 9380\n--- ------`. ```js ({ test: () => { runPython(` from unittest import TestCase TestCase().assertEqual(arithmetic_arranger(["1 + 2", "1 - 9380"]), ' 1 1\\n+ 2 - 9380\\n--- ------')`); } }) ``` `arithmetic_arranger(["3 + 855", "3801 - 2", "45 + 43", "123 + 49"])` should return `3 3801 45 123\n+ 855 - 2 + 43 + 49\n----- ------ ---- -----`. ```js ({ test: () => { runPython(` from unittest import TestCase TestCase().assertEqual(arithmetic_arranger(["3 + 855", "3801 - 2", "45 + 43", "123 + 49"]), ' 3 3801 45 123\\n+ 855 - 2 + 43 + 49\\n----- ------ ---- -----')`); } }) ``` `arithmetic_arranger(["11 + 4", "3801 - 2999", "1 + 2", "123 + 49", "1 - 9380"])` should return `11 3801 1 123 1\n+ 4 - 2999 + 2 + 49 - 9380\n---- ------ --- ----- ------`. ```js ({ test: () => { runPython(` from unittest import TestCase TestCase().assertEqual(arithmetic_arranger(["11 + 4", "3801 - 2999", "1 + 2", "123 + 49", "1 - 9380"]), ' 11 3801 1 123 1\\n+ 4 - 2999 + 2 + 49 - 9380\\n---- ------ --- ----- ------')`); } }) ``` `arithmetic_arranger(["44 + 815", "909 - 2", "45 + 43", "123 + 49", "888 + 40", "653 + 87"])` should return `'Error: Too many problems.'`. ```js ({ test: () => { runPython(` from unittest import TestCase TestCase().assertEqual(arithmetic_arranger(["44 + 815", "909 - 2", "45 + 43", "123 + 49", "888 + 40", "653 + 87"]), 'Error: Too many problems.')`); } }) ``` `arithmetic_arranger(["3 / 855", "3801 - 2", "45 + 43", "123 + 49"])` should return `"Error: Operator must be '+' or '-'."`. ```js ({ test: () => { runPython(` from unittest import TestCase TestCase().assertEqual(arithmetic_arranger(["3 / 855", "3801 - 2", "45 + 43", "123 + 49"]), "Error: Operator must be '+' or '-'.")`); } }) ``` `arithmetic_arranger(["24 + 85215", "3801 - 2", "45 + 43", "123 + 49"])` should return `'Error: Numbers cannot be more than four digits.'`. ```js ({ test: () => { runPython(` from unittest import TestCase TestCase().assertEqual(arithmetic_arranger(["24 + 85215", "3801 - 2", "45 + 43", "123 + 49"]), "Error: Numbers cannot be more than four digits.")`); } }) ``` `arithmetic_arranger(["98 + 3g5", "3801 - 2", "45 + 43", "123 + 49"])` should return `'Error: Numbers must only contain digits.'`. ```js ({ test: () => { runPython(` from unittest import TestCase TestCase().assertEqual(arithmetic_arranger(["98 + 3g5", "3801 - 2", "45 + 43", "123 + 49"]), "Error: Numbers must only contain digits.")`); } }) ``` `arithmetic_arranger(["3 + 855", "988 + 40"], True)` should return `3 988\n+ 855 + 40\n----- -----\n 858 1028`. ```js ({ test: () => { runPython(` from unittest import TestCase TestCase().assertEqual(arithmetic_arranger(["3 + 855", "988 + 40"], True), " 3 988\\n+ 855 + 40\\n----- -----\\n 858 1028")`); } }) ``` `arithmetic_arranger(["32 - 698", "1 - 3801", "45 + 43", "123 + 49", "988 + 40"], True)` should return `32 1 45 123 988\n- 698 - 3801 + 43 + 49 + 40\n----- ------ ---- ----- -----\n -666 -3800 88 172 1028`. ```js ({ test: () => { runPython(` from unittest import TestCase TestCase().assertEqual(arithmetic_arranger(["32 - 698", "1 - 3801", "45 + 43", "123 + 49", "988 + 40"], True), " 32 1 45 123 988\\n- 698 - 3801 + 43 + 49 + 40\\n----- ------ ---- ----- -----\\n -666 -3800 88 172 1028")`); } }) ``` # --seed-- ## --seed-contents-- ```py def arithmetic_arranger(problems, show_answers=False): return problems print(f'\n{arithmetic_arranger(["32 + 698", "3801 - 2", "45 + 43", "123 + 49"])}') ``` # --solutions-- ```py def arithmetic_arranger(problems, result=False): lin1 = "" lin2 = "" lin3 = "" lin4 = "" if len(problems) > 5: return 'Error: Too many problems.' for problem in problems: [num1, sym, num2] = problem.split() sign = ['+', '-'] if sym not in sign: return ("Error: Operator must be '+' or '-'.") if len(num1) > 4 or len(num2) > 4: return ("Error: Numbers cannot be more than four digits.") if not num1.isnumeric() or not num2.isnumeric(): return ("Error: Numbers must only contain digits.") lin1 += " " + num1 + " " if len(num1) >= len( num2) else " " * (len(num2) + 2 - len(num1)) + num1 + " " lin2 += sym + " " + num2 + " " if len(num2) >= len( num1) else sym + " " * (len(num1) - len(num2) + 1) + num2 + " " nmax = (len(num1) + 2) if len(num1) >= len(num2) else (len(num2) + 2) lin3 += "-" * nmax + " " op = int(num1) + int(num2) if sym == "+" else int(num1) - int(num2) lin4 += (" " * (nmax - len(str(op)))) + str(op) + " " arranged_problems = lin1.rstrip() + "\n" + lin2.rstrip( ) + "\n" + lin3.rstrip() if result: arranged_problems += "\n" + lin4.rstrip() return arranged_problems ```