索引两个列表并比较它们的值答案

【问题标题】：Indexing two lists and comparing their values索引两个列表并比较它们的值
【发布时间】：2019-01-03 18:05:11
【问题描述】：

我正在做一个日期时间验证项目。具体来说，确保每个时间间隔都有一个日期时间。如果间隔中缺少日期时间，我会将缺少的值添加到 Timestamp 对象列表中。

当我运行以下代码时，它会将大多数日期时间标记为缺失，即使它们不是。我相信这是一个索引问题。我哪里错了？

代码：

import datetime

_RRATE_ = [0,1,0] #data refresh rate in [minute, hour, day]
LOCALE = "Seattle" #location of cell site

timesList = [] #initialize list of Timestamps with Errors filled in



#Class Timestamp allows us to store all data for a single timestamp in one object.
class Timestamp:
    x = 1 #gives each new timestamp object a unique identifier for the dataset
    missingStamps = 0
    def __init__(self, datetime, location, errorMessage):
        self.timestamp = datetime
        self.location = location
        self.error = errorMessage
        self.UID = Timestamp.x
        Timestamp.x+=1
        timesList.append(self)

    def updateError(self, newError):
        self.error = newError

    def __repr__(self): #make print timesList look neat
        return str(self.UID) + " " + str(self.timestamp) + ", " + self.location + ", " + self.error

def duplicates(index):
    tempList = []
    for timestamp in timesList:
        tempList.append(timestamp.timestamp)
    if datetimes[index] in tempList:
        Timestamp(datetimes[index],LOCALE, "duplicate")
        return True
    else:
        return False

def outOfPlace(index):
    for timestampObj in timesList:
        if(timestampObj.timestamp > datetimes[index]):
            Timestamp(datetimes[index],LOCALE, "out of place")
            return True
        else:
            return False

def missingTimestamp(datetimeObj):
    Timestamp.missingStamps = 0
    if dateAdd(timesList[len(timesList)-1].timestamp) < datetimeObj:
        while dateAdd(timesList[len(timesList)-1].timestamp) < datetimeObj:
            Timestamp(dateAdd(timesList[len(timesList)-1].timestamp), LOCALE, "missing timestamp")
            Timestamp.missingStamps+=1
        return True
    else:
        return False

def dateAdd(datetimeObj):
    return (datetimeObj + datetime.timedelta(minutes = _RRATE_[0], hours = _RRATE_[1], days = _RRATE_[2]))

def main():
    Timestamp(datetimes[0],LOCALE, "no error")
    errorCount = 0
    for i in range(1,len(datetimes)):
        if duplicates(i):
            errorCount+=1
        elif outOfPlace(i):
            errorCount+=1
        elif (missingTimestamp(datetimes[i]))>0:
            errorCount+=Timestamp.missingStamps
            Timestamp.missingStamps = 0
        else:
            Timestamp(datetimes[i],LOCALE, "no error")
    for elem in timesList:
        print elem



b = datetime.datetime(2018,7,20)
c = datetime.datetime(2018,7,20,1)
d = datetime.datetime(2018,7,20,2)
e = datetime.datetime(2018,7,20,7)
f = datetime.datetime(2018,7,20,7)
g = datetime.datetime(2018,7,20,9)
h = datetime.datetime(2018,7,20,16)
i = datetime.datetime(2018,7,20,16)
j = datetime.datetime(2018,7,20,9)

datetimes = [b,c,d,e,f,g,h,i,j]

main()

What is printed

【问题讨论】：

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标签： python python-2.7 indexing

【解决方案1】：

@Prune 在 cmets 中对您的问题指定，您应该对问题进行更完整的描述。

话虽如此，我运行了你的代码，从我得到的输出来看，问题似乎出在主函数中控制流语句的逻辑上，具体来说：

elif (missingTimestamp(datetimes[i]))>0:
        errorCount+=Timestamp.missingStamps
        Timestamp.missingStamps = 0

当遇到缺少时间戳时，例如在d 和e 之间，missingTimestamp 函数会填充直到e 的值，但不包括e，并且在函数返回后控制块不会处理此问题。然后它移动到f，并且e 没有放在你的全局timesList 变量中。

解决问题的一个简单方法是将elif 块更改为：

        elif (missingTimestamp(datetimes[i]))>0:
        errorCount+=Timestamp.missingStamps
        Timestamp.missingStamps = 0
        # Line below to add current value to global timeList variable
        Timestamp(datetimes[i],LOCALE, "no error")

【讨论】：