方案1，较快

operator = ['+', '-', '', '/'] a = input() if '+' not in a and '-' not in a and '' not in a and '/' not in a: print('Invalid operation!') else: for item in operator: if item in a: b, c = map(float, a.split(item)) if c == 0: print('Wrong!Division by zero!') else: print('%.4f%s%.4f=%.4f' % (b, item, c, eval(a)))

方案2，直接遍历

operator = ['+', '-', '*', '/'] a, flag = input(), 0 for ch in a: if ch in operator: b, c = map(float, a.split(ch)) if c == 0: flag = 1 print('Wrong!Division by zero!') else: flag = 1 print('%.4f%s%.4f=%.4f' % (b, ch, c, eval(a))) if flag == 0: print('Invalid operation!')