birarySearchAndMore

#  binary search
#  needs a sorted list

sorted_list = [1, 2, 3, 4, 4, 4, 4, 4, 5, 6, 7, 8, 9]
#[1,2,4,5,8]
def binary_search(asorted_list, avalue):
    left = 0                    # left to 0
    right =len(asorted_list)-1  # right to highest index in list
    while left <= right:        # loop that ends when left > right
        mid = int((left + right)/2) # mid to int between left and right
        #print(left, right, mid)
        if asorted_list[mid] > avalue:
            right = mid - 1       # if sorted_list[mid] > value  set right to mid - 1
            rightdist=round(abs(asorted_list[right]-avalue),3) # nummerical distance from mid
            #print(left, right, mid)
        elif asorted_list[mid] < avalue:
            left = mid + 1
            leftdist=round(abs(asorted_list[left]-avalue),3) # nummerical distance from mid
            #print(left, right, mid)
        else:
            countmid = (asorted_list.count(asorted_list[mid]))  # count number of items
            firstmid =(asorted_list.index(asorted_list[mid]))   # index of the first item
            lastmid = firstmid + countmid -1                    # index of the last item

            return (f"{avalue} was found at position {mid}, {avalue} appears {countmid} times, first occurence postn {firstmid}, last occurence postn {lastmid}  ")
            # location of a found item

    if leftdist > rightdist:
        nearno = asorted_list[right]
        pos = right
    else:
        nearno = asorted_list[left]
        pos = left
    return (f"The search for {avalue} was not found, nearest number is {nearno} at position {pos}")


print(binary_search(sorted_list,4.5))