Python - 仅读取 .csv 日期时间字符串列中的时间，然后将时间转换为 UTC

Question

简而言之，我有一个程序可以打开一个 .csv 文件，读取 .csv 文件，然后将包含日期时间字符串数据的列合并到一个新的 .csv 文件中。但是，在程序将列合并到新文件之前，我首先需要从 datetime 字符串中仅读取时间，然后将时间转换为 UTC，然后将其合并到新的 .csv 文件中。

由于数据存储在 .csv 文件中，当检索到它时，它会以字符串形式出现：

"1/28/2016  3:52:49 PM"

如何仅读取 3:52:49 并将其设为 35249，然后将其转换为 UTC 时间，然后将时间作为新列存储在新的 .csv 文件中？

如果您需要我的代码：

import os
import csv
import datetime as dt
from os import listdir
from os.path import join 
import matplotlib.pyplot as plt

#get the list of files in mypath and store in a list

mypath = 'C:/Users/Alan Cedeno/Desktop/Test_Folder/'
onlycsv = [f for f in listdir(mypath) if '.csv' in f]

#print out all the files with it's corresponding index

for i in range(len(onlycsv)):
    print(i,onlycsv[i])

#prompt the user to select the files

option = input('please select file1 by number: ')
option2 = input('please select file2 by number: ')

#build out the full paths of the files and open them

fullpath1 = join(mypath, onlycsv[option])
fullpath2 = join(mypath, onlycsv[option2])

#create third new.csv file

root, ext = os.path.splitext(fullpath2)
output = root + '-new.csv'

with open(fullpath1) as r1, open(fullpath2) as r2, open(output, 'a') as w:
    writer = csv.writer(w)
    merge_from = csv.reader(r1)
    merge_to = csv.reader(r2)
# skip 3 lines of headers
for _ in range(3):
    next(merge_from)
for _ in range(1):
    next(merge_to)
for merge_from_row, merge_to_row in zip(merge_from, merge_to):
    # insert from col 0 as to col 0
    merge_to_row.insert(1, merge_from_row[2])
    # replace from col 1 with to col 3
    #merge_to_row[0] = merge_from_row[2]
    # delete merge_to rows 5,6,7 completely
    #del merge_to_row[5:8]
    writer.writerow(merge_to_row)

Answer 1

日期时间库就是您要查找的内容：https://docs.python.org/2/library/datetime.html

>>> from datetime import datetime
>>> dt = datetime.strptime("21/11/06 16:30", "%d/%m/%y %H:%M")
>>> dt
datetime.datetime(2006, 11, 21, 16, 30)

使用dt.strftime(format) 将日期转换为您需要的格式

-- 下面是您问题的解决方案，如果您需要进行其他日期操作，上面应该希望将您链接到一些资源

How do I convert local time to UTC in Python?

>>> def local_to_utc(t):
...     secs = time.mktime(t)
...     return time.gmtime(secs)
>>> a = local_to_utc(dt.timetuple())

我们获取结果，并将其传回，然后以所需的格式转储出来

>>> datetime.fromtimestamp(time.mktime(a)).strftime("%H:%m:%S")