Specifying a time from previous day

[David Rushby]

"jrup" <jrup at mail.com> wrote:
> I need to search some log files, but only if they were created after 4:00pm
> the previous day.
> 
> I've looked at the python time module and its documentation, and have
> skimmed mxDateTime documentation. I'm using activestate python 2.1.1 and
> would like to stay with it's native library since it's the one sanctioned by
> our senior nt person (also not sure how it would interact with the
> activestate install, or I'd try it).
> 
> Can someone please point me in the right direction? Is this doable using the
> time module? I haven't had much luck figuring it out, yet.

  It's certainly "doable" using the time module (see below), but
since:

a) the time module is rather low-level
b) mxDateTime is freely available, and high-level
c) you're a self-described newbie

  , why confuse yourself by using the time module?

  I see no reason why installing the eGenix.com mx Base Package would
harm an installation of Activestate Python.

  An mxDateTime-based example appears below (with equivalent code
based on the time module also present, but commented out):
----------------------------------------------------------------
import glob, os
import mx.DateTime as dt
# import time

beginningOfToday = dt.today()
eightHours = dt.DateTimeDelta(0, 8)

# beginningOfToday = time.mktime(list(time.localtime()[:3])
#    + [-1] + [0] * 5)
# eightHours = 60*60 * 8

minTime = beginningOfToday - eightHours
minTimeAsTicks = minTime.ticks()
print 'Will process all log files modified at or later than', minTime

# minTimeAsTicks = beginningOfToday - eightHours
# print 'Will process all log files modified at or later than',
# print time.asctime(time.localtime(minTimeAsTicks))

# logFilenamePattern could be input as a command-line
# argument using sys.argv
logFilenamePattern = r'c:\temp\*.txt'
logFilenames = glob.glob(logFilenamePattern)

# Build a list of relevant log filenames, including only the names of
# files that have been modified at or later than minTimeAsTicks.
relevantLogFilenames = [
    logFilename 
    for logFilename in logFilenames
    if os.stat(logFilename)[8] >= minTimeAsTicks
  ]

for logFilename in relevantLogFilenames:
    logFile = open(logFilename)

    print 'processing %s...' % logFilename
    # Do some processing here.

    logFile.close()