binarychop

'Example binary chop search'

def search(source, matching):
    'search container <source> to find position of <matching>'
    'return 0 for not found or position where found starting from 1'
    lower = 0
    upper = len(source) - 1
    while lower <= upper:  # note the addition of the = sign
        middle = (lower + upper) // 2
        if source[middle] == matching:
            return middle + 1  # human's count from 1
        else:
            if source[middle] < matching:
                lower = middle + 1
            else:
                upper = middle - 1
    return 0


original = [120,158,78,52,1859,2000,15,14,22,24,56]
tests = original[:]
tests.insert(3, 999)  #  number not in list, to check not found works

original.sort()
print('Sorted lists of numbers: ', end='')
print(*original, sep=", ")
print()

for target in tests:
    pos = search(original, target)
    if pos:  # 0 == False, not 0 == True
        print (f"{target:4} found at position {pos:3}")
    else:
        print(f"{target:4} not found")