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- How to subtract a day from a date? 6 answers
如何从日期减去一天? 6个答案
I want to subtract n days from a file's timestamp, but it doesn't seem to be working. I have read this post, and I think I'm close.
我想从文件的时间戳中减去n天,但它似乎没有工作。我看过这篇文章,我觉得我很接近。
This is an excerpt from my code:
这是我的代码的摘录:
import os, time
from datetime import datetime, timedelta
def processData1( pageFile ):
f = open(pageFile, "r")
page = f.read()
filedate = time.strftime('%m/%d/%Y', time.gmtime(os.path.getmtime(pageFile)))
print filedate
end_date = filedate - datetime.timedelta(days=10)
print end_date
Printing filedate
works, so that date is read correctly from the files. It's the subtraction bit that doesn't seem to be working.
打印存档工作正常,以便从文件中正确读取日期。它是减法位似乎不起作用。
Desired output: If filedate
is 06/11/2013, print end_date
should yield 06/01/2013
.
期望的输出:如果提交的是06/11/2013,则打印end_date应该会产生06/01/2013。
2 个解决方案
#1
7
When you use time.strftime()
you are actually converting a struct_time
to a string.
使用time.strftime()时,实际上是将struct_time转换为字符串。
so filedate
is actually a string. When you try to +
or -
a datetime.timedelta
from it, you would get an error. Example -
所以申请实际上是一个字符串。当你尝试+或 - 来自它的datetime.timedelta时,你会收到一个错误。示例 -
In [5]: s = time.strftime('%m/%d/%Y', time.gmtime(time.time()))
In [6]: s
Out[6]: '09/01/2015'
In [8]: s - datetime.timedelta(days=10)
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
<ipython-input-8-fb1d19ed0b02> in <module>()
----> 1 s - datetime.timedelta(days=10)
TypeError: unsupported operand type(s) for -: 'str' and 'datetime.timedelta'
To get a similar behavior to time.gmtime()
to can instead use datetime.datetime.utcfromtimestamp()
, this would provide a datetime object, from which you can subtract the timedelta.
要获得类似于time.gmtime()的行为,可以改为使用datetime.datetime.utcfromtimestamp(),这将提供一个datetime对象,您可以从中减去timedelta。
And then if the end result you want is actually a string, you can use datetime.strftime()
to convert it to string in required format. Example -
然后,如果您想要的最终结果实际上是一个字符串,您可以使用datetime.strftime()将其转换为所需格式的字符串。示例 -
import os
from datetime import datetime, timedelta
def processData1( pageFile ):
f = open(pageFile, "r")
page = f.read()
filedate = datetime.utcfromtimestamp(os.path.getmtime(pageFile)))
print filedate
end_date = filedate - timedelta(days=10)
print end_date #end_date would be a datetime object.
end_date_string = end_date.strftime('%m/%d/%Y')
print end_date_string
#2
10
cleaned up import
清理了进口
from datetime import datetime, timedelta
start = '06/11/2013'
start = datetime.strptime(start, "%m/%d/%Y") #string to date
end = start - timedelta(days=10) # date - days
print start,end
#1
7
When you use time.strftime()
you are actually converting a struct_time
to a string.
使用time.strftime()时,实际上是将struct_time转换为字符串。
so filedate
is actually a string. When you try to +
or -
a datetime.timedelta
from it, you would get an error. Example -
所以申请实际上是一个字符串。当你尝试+或 - 来自它的datetime.timedelta时,你会收到一个错误。示例 -
In [5]: s = time.strftime('%m/%d/%Y', time.gmtime(time.time()))
In [6]: s
Out[6]: '09/01/2015'
In [8]: s - datetime.timedelta(days=10)
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
<ipython-input-8-fb1d19ed0b02> in <module>()
----> 1 s - datetime.timedelta(days=10)
TypeError: unsupported operand type(s) for -: 'str' and 'datetime.timedelta'
To get a similar behavior to time.gmtime()
to can instead use datetime.datetime.utcfromtimestamp()
, this would provide a datetime object, from which you can subtract the timedelta.
要获得类似于time.gmtime()的行为,可以改为使用datetime.datetime.utcfromtimestamp(),这将提供一个datetime对象,您可以从中减去timedelta。
And then if the end result you want is actually a string, you can use datetime.strftime()
to convert it to string in required format. Example -
然后,如果您想要的最终结果实际上是一个字符串,您可以使用datetime.strftime()将其转换为所需格式的字符串。示例 -
import os
from datetime import datetime, timedelta
def processData1( pageFile ):
f = open(pageFile, "r")
page = f.read()
filedate = datetime.utcfromtimestamp(os.path.getmtime(pageFile)))
print filedate
end_date = filedate - timedelta(days=10)
print end_date #end_date would be a datetime object.
end_date_string = end_date.strftime('%m/%d/%Y')
print end_date_string
#2
10
cleaned up import
清理了进口
from datetime import datetime, timedelta
start = '06/11/2013'
start = datetime.strptime(start, "%m/%d/%Y") #string to date
end = start - timedelta(days=10) # date - days
print start,end