計算將港鐵車程拆開以減低車費的車程組合
本人並不確保本文的準確性，對任何損失或傷害概不負責，亦非鼓吹這樣做，只為作出簡單的計算供參考。本文提及的車費於本文刊登日有效。
眾所周知，如果在某些港鐵站前往羅湖或落馬洲，在上水出閘再原站入閘，總車費有可能會減少。我嘗試利用以下的小程式，計算出成人車票，包括八達通及單程車票，在港鐵系統內有可能因中途出閘再入閘而便宜了的組合。
先到政府資料一線通網站下載最新的港鐵車費表 mtr_lines_fares.csv（不包括輕鐵）。
再執行以下程式：
#!/usr/bin/env python
import csv
from math import ceil
octopusFareList = {}
ticketFareList = {}
stationList = {}
"""
field available
"SRC_STATION_NAME",
"SRC_STATION_ID",
"DEST_STATION_NAME",
"DEST_STATION_ID",
"OCT_ADT_FARE",
"OCT_STD_FARE",
"SINGLE_ADT_FARE",
"OCT_CON_CHILD_FARE",
"OCT_CON_ELDERLY_FARE",
"OCT_CON_PWD_FARE",
"SINGLE_CON_CHILD_FARE",
"SINGLE_CON_ELDERLY_FARE"
"""
with open('mtr_lines_fares.csv', 'rb') as csvfile:
reader = csv.DictReader(csvfile, delimiter=',')
for row in reader:
if (row['SRC_STATION_ID'] == row['DEST_STATION_ID']):
continue
srcId = int(row['SRC_STATION_ID'])
destId = int(row['DEST_STATION_ID'])
octopusFareList[srcId,destId] = float(row['OCT_ADT_FARE'])
ticketFareList[srcId,destId] = float(row['SINGLE_ADT_FARE'])
stationList[srcId] = row["SRC_STATION_NAME"]
# print octopusFareList[100,22]
# 1 = Central, 39 = Hong Kong , 3 = TST ,80 = ETST ,exclude these cases
centralStdId = 1
hongKongStdId = 39
tstStdId = 3
etstStdId = 80
print '"TYPE","START","OUT_AND_IN","END","OLD","NEW","SAVE"'
for i in range(1,121):
for j in range(1,121):
if i == j or (i == centralStdId and j == hongKongStdId) or (i == hongKongStdId and j == centralStdId) or (i == etstStdId and j == tstStdId)or (i == tstStdId and j == etstStdId):
continue
if (i,j) not in octopusFareList.keys():
continue
for x in range(1,121):
if x == i or x == j or (i == centralStdId and x == hongKongStdId) or (i == hongKongStdId and x == centralStdId) or (i == etstStdId and x == tstStdId)or (i == tstStdId and x == etstStdId) or (j == centralStdId and x == hongKongStdId) or (j == hongKongStdId and x == centralStdId) or (j == etstStdId and x == tstStdId)or (j == tstStdId and x == etstStdId):
continue
if (i,x) not in octopusFareList.keys():
continue
if (x,j) not in octopusFareList.keys():
continue
# normal octopus case
newOctupusFare = octopusFareList[i,x] + octopusFareList[x,j]
if newOctupusFare <= octopusFareList[i,j] - 0.01:
print '"OCTOPUS","' + stationList[i] + '","' + stationList[x] + '","' + stationList[j] + '",' + str(octopusFareList[i,j]) + "," + str(newOctupusFare) + "," + str(octopusFareList[i,j] - newOctupusFare)
# 2nd trip discount
newOctupusFare = octopusFareList[i,x] + ceil(octopusFareList[x,j] * 0.9*10.0)/10.0
if newOctupusFare <= octopusFareList[i,j] - 0.01:
print '"OCTOPUS(2nd trip)","' + stationList[i] + '","' + stationList[x] + '","' + stationList[j] + '",' + str(octopusFareList[i,j]) + "," + str(newOctupusFare) + "," + str(octopusFareList[i,j] - newOctupusFare)
# single trip ticket
newTicketFare = ticketFareList[i,x] + ticketFareList[x,j]
if newTicketFare <= ticketFareList[i,j] - 0.01:
print '"TICKET","' + stationList[i] + '","' + stationList[x] + '","' + stationList[j] + '",'+ str(ticketFareList[i,j]) + "," + str(newTicketFare) + "," + str(ticketFareList[i,j] - newTicketFare)
# Handle TST and ETST
if (i != tstStdId) and (j != etstStdId) and (i != etstStdId) and (j != tstStdId):
# normal octopus case
newOctupusFare = octopusFareList[i,tstStdId] + octopusFareList[etstStdId,j]
if newOctupusFare <= octopusFareList[i,j] - 0.01:
print '"OCTOPUS","' + stationList[i] + '","' + stationList[tstStdId] + "->" + stationList[etstStdId] + '","' + stationList[j] + '",' + str(octopusFareList[i,j]) + "," + str(newOctupusFare) + "," + str(octopusFareList[i,j] - newOctupusFare)
# 2nd trip discount
newOctupusFare = octopusFareList[i,tstStdId] + ceil(octopusFareList[etstStdId,j] * 0.9*10.0)/10.0
if newOctupusFare <= octopusFareList[i,j] - 0.01:
print '"OCTOPUS(2nd trip)","' + stationList[i] + '","' + stationList[tstStdId] + "->" + stationList[etstStdId] + '","' + stationList[j] + '",' + str(octopusFareList[i,j]) + "," + str(newOctupusFare) + "," + str(octopusFareList[i,j] - newOctupusFare)
# single trip ticket
newTicketFare = ticketFareList[i,tstStdId] + ticketFareList[etstStdId,j]
if newTicketFare <= ticketFareList[i,j] - 0.01:
print '"TICKET","' + stationList[i] + '","' + stationList[tstStdId] + "->" + stationList[etstStdId] + '","' + stationList[j] + '",'+ str(ticketFareList[i,j]) + "," + str(newTicketFare) + "," + str(ticketFareList[i,j] - newTicketFare)
# normal octopus case
newOctupusFare = octopusFareList[i,etstStdId] + octopusFareList[tstStdId,j]
if newOctupusFare <= octopusFareList[i,j] - 0.01:
print '"OCTOPUS","' + stationList[i] + '","' + stationList[etstStdId] + "->" + stationList[tstStdId] + '","' + stationList[j] + '",' + str(octopusFareList[i,j]) + "," + str(newOctupusFare) + "," + str(octopusFareList[i,j] - newOctupusFare)
# 2nd trip discount
newOctupusFare = octopusFareList[i,etstStdId] + ceil(octopusFareList[tstStdId,j] * 0.9*10.0)/10.0
if newOctupusFare <= octopusFareList[i,j] - 0.01:
print '"OCTOPUS(2nd trip)","' + stationList[i] + '","' + stationList[etstStdId] + "->" + stationList[tstStdId] + '","' + stationList[j] + '",' + str(octopusFareList[i,j]) + "," + str(newOctupusFare) + "," + str(octopusFareList[i,j] - newOctupusFare)
# single trip ticket
newTicketFare = ticketFareList[i,etstStdId] + ticketFareList[tstStdId,j]
if newTicketFare <= ticketFareList[i,j] - 0.01:
print '"TICKET","' + stationList[i] + '","' + stationList[etstStdId] + "->" + stationList[tstStdId] + '","' + stationList[j] + '",'+ str(ticketFareList[i,j]) + "," + str(newTicketFare) + "," + str(ticketFareList[i,j] - newTicketFare)
執行後，可得出一萬多項結果。我將結果輸出到一個 csv file，可到此下載。
以下為部分結果：
第一列為車票種類，有八達通、第二程八達通可享九折的車程（詳情）和單程車票。
第二列為起點車站，本例選取了大埔墟作為起點。
第三列為中途出閘再入閘（單程車票需重新購票）的車站。
第四列為終點車站。
第五及第六列分別為原來車費及新車費。
第七列為可節省的車費。
本文連結