Question

我正在尝试计算从创建和更新文件到当前时刻的时间差，以计算丢失数据的数量。但我无法正确减去它们。我的代码如下。

文件中的数据如下所示：

DATE,temp1
2017-08-14 17:10:01,0.44
2017-08-14 17:15:01,0.62
2017-08-14 17:20:01,0.99
2017-08-14 17:25:01,0.85
2017-08-14 17:30:01,0.13
2017-08-14 17:35:01,0.24
2017-08-14 17:40:02,0.95
2017-08-14 17:45:01,0.65

代码是：

#!/usr/bin/env python
# -*-coding:utf-8 -*
import os
import sys
import time

from time import mktime, strftime, localtime, sleep
from datetime import datetime, timedelta

def missing_data(expect, missed):
.
.
.
. 

def main():
    fmt = '%Y-%m-%d %H:%M:%S'
    with open('/home/kamil/Desktop/sensor1/temp.dat', 'rb') as f:
        read = f.readlines()[1:]
        for line in read:
            line = line.strip().split(',')
            # print line
            start_date = line[0]  # type is str so i convert it to datetime
            start_date = datetime.strptime(start_date, fmt) # type is datetime.datetime  and here I need the first timestamp in the file only
            current_time = datetime.now()
            step_size = 5
            differ_time = current_time - start_date
            minutes_values = differ_time.total_seconds() / 60
            print 'minutes_values:::::::::::::::::::', minutes_values
            missed = int(minutes_values / step_size)
            expected = .........
            missing_data(expected, missed)    


if __name__ == '__main__':
    main()

如果我打印minutes_values，它会给我这样的结果：

但我只需要最后一个值，例如40.755。我是编码的新手。在这方面，有人可以帮助我如何获得单一价值。

Answer 1

首先，创建一个列表来保存minutes_values，然后使用builtin max（）来获取最大值。

def main():
    fmt = '%Y-%m-%d %H:%M:%S'
    with open('/home/kamil/Desktop/sensor1/temp.dat', 'rb') as f:
        read = f.readlines()[1:]
        minutes_values = []
        for line in read:
            line = line.strip().split(',')
            # print line
            start_date = line[0]  # type is str so i convert it to datetime
            start_date = datetime.strptime(start_date, fmt) # type is datetime.datetime  and here I need the first timestamp in the file only
            current_time = datetime.now()
            step_size = 5
            differ_time = current_time - start_date
            minutes_values.append( differ_time.total_seconds() / 60 )
            missed = int(minutes_values / step_size)
            expected = .........
            missing_data(expected, missed) 

    print 'minutes_values:::::::::::::::::::', max(minutes_values)

Answer 2

我也是初学者，但在我看来，for循环是不必要的。看起来你只想要循环返回的第一个值（40.755）并且每个连续的值减少五个，这与你的步长= 5有关？如果更改step_size，请按连续时间更改该数量吗？

如果for循环对于其他东西是必要的，则将代码的两个部分分开：一个用于计算时间差异，一个用于执行for循环正在执行的操作。

从python中的csv文件的当前日期时间减去日期时间

2 个答案: