Find First and Last Position of Element in Sorted Array

def searchRange(nums, target):
    first = last = -1
    for i, value in enumerate(nums):
        if value == target:
            if first == -1:
                first = i  # the first match fixes the start
            last = i  # every later match moves the end
    return [first, last]

def searchRange(nums, target):
    # An ordinary binary search finds some copy of target, if there is one.
    lo, hi = 0, len(nums) - 1
    found = -1
    while lo <= hi:
        mid = (lo + hi) // 2
        if nums[mid] == target:
            found = mid
            break
        if nums[mid] < target:
            lo = mid + 1
        else:
            hi = mid - 1
    if found == -1:
        return [-1, -1]
    # The copies sit next to each other, so walk out to both ends of the run.
    first = last = found
    while first > 0 and nums[first - 1] == target:
        first -= 1
    while last < len(nums) - 1 and nums[last + 1] == target:
        last += 1
    return [first, last]

def lowerBound(nums, value):
    # The first index whose number is at least value, or len(nums) if none is.
    lo, hi = 0, len(nums)
    while lo < hi:
        mid = (lo + hi) // 2
        if nums[mid] < value:
            lo = mid + 1  # nums[mid] and everything before it is too small
        else:
            hi = mid  # nums[mid] qualifies, but an earlier index might too
    return lo


def searchRange(nums, target):
    first = lowerBound(nums, target)
    if first == len(nums) or nums[first] != target:
        return [-1, -1]
    # The run of target ends right before the first number above target.
    last = lowerBound(nums, target + 1) - 1
    return [first, last]