pyBoardingList2

# Arrange a boarding list for passengers on a plane, starting from the rear (higher row numbers)
# and boarding those furthest from an aisle first

def makeBoardingList(aisles, seatcodes):
    aislePos = []
    # create a  list of numeric values that represent the aisle positions
    for pair in aisles:
        aislePos.append((ord(pair[0]) + ord(pair[1])) / 2)

    output = []
    for seat in seatcodes:
        # First find the distance of this seat from each aisle
        # and choose the nearest aisle to this seat. This gives the primary sort key.
        alist = [abs(ord(seat[-1]) - pos) for pos in aislePos]
        minDist = min(alist)
        aisleValue = 10000 * alist.index(minDist)
        sequence = aisleValue + int(seat[:-1]) * 100 + minDist
        output.append((sequence, seat))

    return sorted(output, reverse=True)


# 12 seats across. Aisles between seats C and D, and I and J
aisleSeats = ["CD", "IJ"]
inlist = ["7I", "8A", "2B", "7H", "6D", "6L", "4C", "8F", "1B", "7C", "10B",
          "6A", "7G", "7F", "8C", "11A", "9B", "6B", "6F", "6K", "9H", "10G"]

outlist = makeBoardingList(aisleSeats, inlist)
lastseq = 999999
aisleNum = 1
for tup in outlist:
    if (lastseq - tup[0]) > 5000:       # test for change of aisle
        print("\nAisle", aisleNum)
        aisleNum += 1
    lastseq = tup[0]
    print(tup[1], end="  ")
print()

# Output:-
# Aisle 1
# 10G  9H  7G  7H  7I  6L  6K
# Aisle 2
# 11A  10B  9B  8F  8A  8C  7F  7C  6F  6A  6B  6D  4C  2B  1B