python - 对两列求和，在MapReduce中计算最大值，最小值和平均值

Question

我有一个映射器的示例代码，如下所示，键是UCO，值是TaxiTotal，应为TaxiIn和TaxiOut两列的总和，如何对这两列求和？

我当前的解决方案TaxiIn + TaxiOut会导致粘贴编号，例如333 + 444 = 333444，我需要将其设为777，如何编写代码？

#! /usr/bin/env python

import sys

# -- Airline Data
# Year, Month, DayofMonth, DayOfWeek, DepTime, CRSDepTime, ArrTime, CRSArrTime, UniqueCarrier, FlightNum,
# TailNum, ActualElapsedTime, CRSElapsedTime, AirTime, ArrDelay, DepDelay, Origin, Dest,         Distance, TaxiIn,
# TaxiOut, Cancelled, CancellationCode, Diverted, CarrierDelay, WeatherDelay, NASDelay, SecurityDelay, LateAircraftDelay

for line in sys.stdin:
    line = line.strip()
    unpacked = line.split(",")
    Year, Month, DayofMonth, DayOfWeek, DepTime, CRSDepTime, ArrTime, CRSArrTime, UniqueCarrier, FlightNum, TailNum, ActualElapsedTime, CRSElapsedTime, AirTime, ArrDelay, DepDelay, Origin, Dest, Distance, TaxiIn,TaxiOut, Cancelled, CancellationCode, Diverted, CarrierDelay, WeatherDelay, NASDelay, SecurityDelay, LateAircraftDelay = line.split(",")
    UCO = "-".join([UniqueCarrier, Origin])
    results = [UCO, TaxiIn+TaxiOut]
    print("\t".join(results))

Answer 1

将TaxiIn + TaxiOut转换为:

int(TaxiIn) + int(TaxiOut)

请参见以下示例:

In [1612]: TaxiIn = '333'                                                                                                                                                                                   

In [1613]: TaxiOut = '444'                                                                                                                                                                                  

In [1614]: TaxiIn + TaxiOut                                                                                                                                                                                 
Out[1614]: '333444'

In [1615]: int(TaxiIn) + int(TaxiOut)                                                                                                                                                                       
Out[1615]: 777

您不能有字符串的数字和，因为它会将 str转换为 int或 float。

您的代码应为:

results = [UCO, str(int(TaxiIn) + int(TaxiOut))]
print("\t".join(results))