27. Remove Element leetcode python 2016 new season

Given an array and a value, remove all instances of that value in place and return the new length.

The order of elements can be changed. It doesn't matter what you leave beyond the new length.

the problem require constant space .

we need a count to maintain non-duplicate numbers and an index to iterate through

class Solution(object):
    def removeElement(self, nums, val):
        """
        :type nums: List[int]
        :type val: int
        :rtype: int
        """
        nums_length = len(nums)
        if nums_length < 2:
            return nums_length
        count = 1
        index = 1
        while index < nums_length - 1:
            if nums[index] != nums[index]:
                nums[count] = nums[index]
                count += 1
            index += 1
        return count