如何获取最新文件

Question

i am newbie in Python language and i need write a code that list directory that contains files with random names, for example:

JuniperAccessLog-standalone-FCL_VPN-20120319-1110.gz
JuniperAccessLog-standalone-FCL_VPN-20120321-1110.gz

I need get the more recent file

I try this, but without success.

import os
from datetime import datetime 

t = datetime.now()
archive = t.strftime("JuniperAccessLog-standalone-FCL_VPN-%Y%m%d-%H*.gz")
file = os.popen(archive)

Result:

sh: JuniperAccessLog-standalone-FCL_VPN-20120320-10*.gz: command not found

have a possibility the use this logic ?

Answer 1

If you want the most recent file, you could take advantage of the fact that they appear to sort into date time order:

import os

logdir='.' # path to your log directory

logfiles = sorted([ f for f in os.listdir(logdir) if f.startswith('JuniperAccessLog-standalone-FCL_VPN')])

print "Most recent file = %s" % (logfiles[-1],)

Answer 2

You should be able to get what you want using the glob module:

def GetLatestArchive():
    "Return the most recent JuniperAccessLog file for today's date."

    import glob
    from datetime import datetime 

    archive_format = datetime.now().strftime("JuniperAccessLog-standalone-FCL_VPN-%Y%m%d-%H*.gz")
    archives = glob.glob(archive_format)

    if len(archives) > 0:
        # The files should come sorted, return the last one in the list.
        return archives[-1]
    else:
        # No files were matched
        return None

Answer 3

glob will do what you are trying to do with with your popen call.

import os
import glob
from datetime import datetime 

t = datetime.now()
archive = t.strftime("JuniperAccessLog-standalone-FCL_VPN-%Y%m%d-%H*.gz")
files = glob.glob(archive)
for f in files:
   # do something with f

Answer 4

1. Define a function to parse the date out of the filename:

    def date_from_path(path): m = re.match(r"JuniperAccessLog-standalone-FCL_VPN-(\\d+)-(\\d+).\\gz", path) return int(m.group(1)), int(m.group(2)) 

   This function uses the fact that your date and time values are representable as integers.

2. Use max to get the most recent file:

    max(os.listdir(directory), key=date_from_path)