removeElement.py

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

# Do not allocate extra space for another array, you must do this by modifying the input array in-place with O(1) extra memory.

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

# Example 1:

# 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.
# Example 2:

# Given nums = [0,1,2,2,3,0,4,2], val = 2,

# Your function should return length = 5, with the first five elements of nums containing 0, 1, 3, 0, and 4.

# Note that the order of those five elements can be arbitrary.

# It doesn't matter what values are set beyond the returned length.
# Clarification:

# Confused why the returned value is an integer but your answer is an array?

# Note that the input array is passed in by reference, which means modification to the input array will be known to the caller as well.

# Internally you can think of this:

# // nums is passed in by reference. (i.e., without making a copy)
# int len = removeElement(nums, val);

# // any modification to nums in your function would be known by the caller.
# // using the length returned by your function, it prints the first len elements.
# for (int i = 0; i < len; i++) {
#     print(nums[i]);
# }

def removeElement(nums, val) -> int:
    index = 0
    running_index = -1
    while index < len(nums):
        if nums[index] == val:
            pass
        else:
            running_index += 1
            nums[running_index] = nums[index]
    
        index += 1
    return(running_index+1)

nums = [0,1,2,2,3,0,4,2]
val = 2
ans = removeElement(nums, 2)
print(ans)