On 06Nov2018 18:10, Alan Gauld <alan.ga...@yahoo.co.uk> wrote: >On 06/11/2018 13:13, Asad wrote: > >> Can you provide some advice and code for the following problem : > >The first thing is to go read the documentation for the os.path module. >It is designed for reliable path manipulation. > >> /a/b/c/d/test/test_2814__2018_10_05_12_12_45/logA.log >> >> f3 = open ( r"/a/b/c/d/test/test_2814__2018_10_05_12_12_45/logA.log", 'r' ) >> st1 = f3.readlines () > >You hardly ever need readlines() any more, just iterate >over the file, its much easier. > >> for j in range ( len ( st1 ) ): > >for line in f3:
Not to mention cheaper in memory usage. [...snip...] >> a = mo.group() ## 123456/789 >> =================================================================== >> How to do I traverse to the required directory which is >> /a/b/c/d/test/123456/789 ? > >You can use relative paths in os.chdir. >So a payth of '..' will be one level up from the current >directory. Of course you need to chdir to that directory first >but os.path will tell you the dir you need. It is better to just construct the required path. Chdir there requires a chdir back, and chdir affects all the relative paths your programme may be using. I'd use os.path.dirname to get '/a/b/c/d/test' and then just append to it with os.path.join to contruct each directory path. [...] >But I'm guessing that's too obvious so the path may vary? >> 1) First I need to extract /a/b/c/d/test/ from >> /a/b/c/d/test/test_2814__2018_10_05_12_12_45/logA.log ? Use os.path.dirname: # up the top from os.path import dirname, join # later testdir = dirname(logfile_path) >get the dir then chdir to .. from there. > >> 2) Then add 123456/789 and create directory location as >> /a/b/c/d/test/123456/789 > >Simple string manipulation or use the os.path functions. Eg dirpath = join(testdir, '123456/789') >> 3) cd /a/b/c/d/test/123456/789 > >os.chdir() I still recommend avoiding this. Just construct the full path to what you need. >> 4) look for the latest file in the directory /a/b/c/d/test/123456/789 > >Slightly more complex, you need the creation timestamp. >You can find that with os.path.getctime() (or several >other options, eg os.stat) Do not use ctime, it is _not_ "creation" time. It is "last change to inode" time. It _starts_ as creation time, but a chmod or even a link/unlink can change it: anything that changes the metadata. Generally people want mtime (last nmodified time), which is the last time the file data got changed. It is more meaningful. Cheers, Cameron Simpson <c...@cskk.id.au> _______________________________________________ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
