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Someone000 发表于 2020-3-25 19:05:09

Type error 的问题

def question(heads, legs):
    rabbit_number_max = legs // 4
    rabbit_number = 0
    while True:
      chicken_number = (legs - rabbit_number * 4) / 2
      if chicken_number == int(chicken_number) and rabbit_number + chicken_number == heads:
            return (chicken_number, rabbit_number)
      elif rabbit_number <= rabbit_number_max:
            rabbit_number += 1
      else:
            print('题目错误啦*_*！此题无解！')

def number(heads, legs):
    if heads <= 0 or heads != int(heads):
      print('头的参数错误T_T！请输入一个正整数！')
      heads = float(input('请重新输入头的个数：'))
      
    elif legs <= 0 or legs != int(legs):
      print('脚的参数错误T_T！请输入一个正整数！')
      legs = float(input('请重新输入：'))
      
    else:
      return(heads, legs)

heads = float(input('请输入头的个数：'))
legs = float(input('请输入脚的个数：'))
(true_heads, true_legs) = number(heads, legs)
(chicken_number, rabbit_number) = question(true_heads, true_legs)
print('鸡的个数是%d, 兔的个数是%d' % (int(chicken_number), int(rabbit_number)))


请输入头的个数：34.5
请输入脚的个数：94
头的参数错误T_T！请输入一个正整数！
请重新输入头的个数：35
Traceback (most recent call last):
File "C:/Users/Documents/学习/python/作业簿/鸡兔同笼.py", line 27, in <module>
    (true_heads, true_legs) = number(heads, legs)
TypeError: cannot unpack non-iterable NoneType object

永恒的蓝色梦想 发表于 2020-3-25 19:38:59

def question(heads, legs):
    rabbit_number_max = legs // 4
    rabbit_number = 0
    while True:
      chicken_number = (legs - rabbit_number * 4) / 2
      if chicken_number == int(chicken_number) and rabbit_number + chicken_number == heads:
            return (chicken_number, rabbit_number)
      elif rabbit_number <= rabbit_number_max:
            rabbit_number += 1
      else:
            print('题目错误啦*_*！此题无解！')

def number(heads, legs):
    if heads <= 0 or heads != int(heads):
      print('头的参数错误T_T！请输入一个正整数！')
      heads = float(input('请重新输入头的个数：'))
      
    elif legs <= 0 or legs != int(legs):
      print('脚的参数错误T_T！请输入一个正整数！')
      legs = float(input('请重新输入：'))
      
    return(heads, legs)

heads = float(input('请输入头的个数：'))
legs = float(input('请输入脚的个数：'))
(true_heads, true_legs) = number(heads, legs)
(chicken_number, rabbit_number) = question(true_heads, true_legs)
print('鸡的个数是%d, 兔的个数是%d' % (int(chicken_number), int(rabbit_number)))

txxcat 发表于 2020-3-25 19:47:04

几个错误，解释看代码里的注释：
def question(heads, legs):
    rabbit_number_max = legs // 4
    rabbit_number = 0
    while True:
      chicken_number = (legs - rabbit_number * 4) / 2
      if chicken_number == int(chicken_number) and rabbit_number + chicken_number == heads:
            return (chicken_number, rabbit_number)
      elif rabbit_number <= rabbit_number_max:
            rabbit_number += 1
      else:
            print('题目错误啦*_*！此题无解！')
            break         #无解就无限循环了，至少加个break吧，然后默认返回None


def number(heads, legs):
    if heads <= 0 or heads != int(heads):
      print('头的参数错误T_T！请输入一个正整数！')
      heads = float(input('请重新输入头的个数：'))
#没有返回呀，默认返回None      
    elif legs <= 0 or legs != int(legs):
      print('脚的参数错误T_T！请输入一个正整数！')
      legs = float(input('请重新输入：'))
#同上      
#    else:这样改就有正常的返回了
    return(heads, legs)

heads = float(input('请输入头的个数：'))
legs = float(input('请输入脚的个数：'))
(true_heads, true_legs) = number(heads, legs)
if question(true_heads, true_legs)!=None:   #加个判断，不然无解还运行下面语句就报错
    (chicken_number, rabbit_number) = question(true_heads, true_legs)
    print('鸡的个数是%d, 兔的个数是%d' % (int(chicken_number), int(rabbit_number)))

dlnb526 发表于 2020-3-25 19:48:00

同意楼上两位的代码。（至少可以顺利执行）
出现错误的原因是当遇到其他情况时number函数并不会返回一个元组，这样就没有办法再把参数传入question函数。
在你的实验中，输出了
头的参数错误T_T！请输入一个正整数！
之后，会直接执行下一行代码
(chicken_number, rabbit_number) = question(true_heads, true_legs)
因此return需要在任何条件都实现才可以继续进行。除了楼上的解决方式，你还可以：
1.在number函数中添加一个while循环以保证输入正确时才会跳出函数
2.在执行代码区使用try except语句避免报错

希望对你有所帮助

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