https://leetcode-cn.com/problems/move-zeroes/
    需要注意的点

    1. python 没有自加，https://www.runoob.com/note/24457， https://www.runoob.com/python/python-func-id.html
    2. 该题用到了快慢指针 ```python class Solution(object): def moveZeroes(self, nums):
      1.  """
      2.  :type nums: List[int]
      3.  :rtype: None Do not return anything, modify nums in-place instead.
      4.  """
      5.  index = self.removeElement(nums, 0)
      6.  # 将数组index后面的元素赋0
      7.  while index < len(nums):
      8.      nums[index] = 0
      9.      index += 1
      10.  return nums
    def removeElement(self, nums, val):
    """
        快慢指针， 快指针总是在增加，
        慢指针只有在符合条件的时候才增加
    """

    fast = 0
    slow = 0
    while fast < len(nums):
        # slow 符合条件才增加，该题条件是 当fast != val
        if nums[fast] != val:
            nums[slow] = nums[fast]
            slow += 1

        # fast 总是增加
        fast += 1

    return slow

    ```python
class Solution(object):
    def moveZeroes(self, nums):
        """
        :type nums: List[int]
        :rtype: None Do not return anything, modify nums in-place instead.
        """
        # index = self.removeElement(nums, 0)
        fast = 0
        slow = 0
        while fast < len(nums):
            # slow 符合条件才增加，该题条件是 当fast != val
            if nums[fast] != 0:
                nums[slow] = nums[fast]
                slow += 1

            # fast 总是增加
            fast += 1

        while slow < len(nums):
            nums[slow] = 0
            slow += 1
        return nums



    def removeElement(self, nums, val):
        """
            快慢指针， 快指针总是在增加，
            慢指针只有在符合条件的时候才增加
        """
        pass