# 27\_Remove Element

Given an array `nums` *and a value* `val`, remove all instances of that value [**in-place**](https://en.wikipedia.org/wiki/In-place_algorithm) and return the new length.

Do not allocate extra space for another array, you must do this by **modifying the input array** [**in-place**](https://en.wikipedia.org/wiki/In-place_algorithm) with O(1) extra memory.

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

## **Example:**

```
Given nums = [3,2,2,3], val = 3,
Your function should return length = 2, with the first two elements of nums being 2.
It doesn't matter what you leave beyond the returned length.
```

## Solution:

```python
def removeElement(nums, val):
    """
    :type nums: List[int]
    :type val: int
    :rtype: int
    """
    # corner cases
    if len(nums) == 0:
        return 0

    write_index = 0
    for i in range(len(nums)):
        if nums[i] != val:
            nums[write_index], nums[i] = nums[i], nums[write_index]
            write_index += 1
    return write_index
```


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