List-2 > sum13编码bat问题：'int‘对象不可迭代

Question

我的代码有问题。问题是：

返回数组中数字的和，返回空数组的0。除了数字13是非常不吉利的，所以它不计数和数字后面的一个13也不算数。来自：https://codingbat.com/prob/p167025

def sum13(nums):
  if not nums:
    return 0
  for x in nums:
    if x == 13:
      break
    return sum(x)
    if 13 not in nums:
      return sums(nums)

问题是，我不能组合和(X)，每次尝试它都会产生一个错误。有人能告诉我为什么吗？

Answer 1

错误的return是这里的许多问题之一，但它可能是修复逻辑的良好开端。很难找出一个问题，一旦解决了，就会产生预期的结果。相反，存在一个普遍的问题，即实现与任务逻辑无关。

通常，您会将问题分解为简单的砖块，有点像这样：

def sum13(nums):
    # "Return the sum of the numbers in the array" 
    #  - let's iterate the array, increasing the sum
    res = 0
    previous_is_13 = False  # introduced later

    # "returning 0 for an empty array."
    # for loop will do nothing on empty arrays, as desired
    for i in nums:  
        # "Except the number 13 is very unlucky, so it does not count"
        # so, let's guard it with an if:
        if i == 13:
            # "numbers that come immediately after a 13 also do not count."
            # ok, let's set a flag to indicate that and clear it once we're past 13
            previous_is_13 = True
            continue

        if previous_is_13:
            previous_is_13 = False  # clear the flag and proceed to the next item
            continue
        res += i
    return res

一旦有了基线解决方案，就会变得更好(如使用迭代器)：

def sum13(nums):
    return sum(value for i, value in enumerate(nums)
               if value!= 13 and (not i or nums[i-1] != 13))