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Tag: file

Do I understand os.walk right?

The loop for root, dir, file in os.walk(startdir) works through these steps? get root of start dir : C:dir1dir2startdir get folders in C:dir1dir2startdir and return list of folders “dirlist” get files in the first dirlist item and return the list of files “filelist” as the first item of a list of filelists. move to the second item in dirlist and

Print file age in seconds using Python

I need my script to download a new file, if the old one is old enough. I set the maximum age of file in seconds. So that I would get back on track with my script writing I need example code, where file age is printed out in seconds. Answer This shows how to find a file’s (or directory’s) last

Can’t download YouTube video

I’m having trouble retrieving the YouTube video automatically. Here’s the code. The problem is the last part. download = urllib.request.urlopen(download_url).read() There’s an error message (thanks Wooble): Answer The code on the original question relies on several assumptions about the content of YouTube pages and URLs (expressed in constructs such as “url.split(‘something=’)[1]”) which may not always be true. I tested it

Inexpensive ways to add seek to a filetype object

PdfFileReader reads the content from a pdf file to create an object. I am querying the pdf from a cdn via urllib.urlopen(), this provides me a file like object, which has no seek. PdfFileReader, however uses seek. What is the simple way to create a PdfFileReader object from a pdf downloaded via url. Now, what can I do to avoid

How to read specific lines from a file (by line number)?

I’m using a for loop to read a file, but I only want to read specific lines, say line #26 and #30. Is there any built-in feature to achieve this? Answer If the file to read is big, and you don’t want to read the whole file in memory at once: Note that i == n-1 for the nth line.

Read from File, or STDIN

I’ve written a command line utility that uses getopt for parsing arguments given on the command line. I would also like to have a filename be an optional argument, such as it is in other utilities like grep, cut etc. So, I would like it to have the following usage How can I implement the following? if a filename is

Check if object is file-like in Python

File-like objects are objects in Python that behave like a real file, e.g. have a read() and a write method(), but have a different implementation from file. It is realization of the Duck Typing concept. It is considered a good practice to allow a file-like object everywhere where a file is expected so that e.g. a StringIO or a Socket

Size of an open file object

Is there a way to find the size of a file object that is currently open? Specifically, I am working with the tarfile module to create tarfiles, but I don’t want my tarfile to exceed a certain size. As far as I know, tarfile objects are file-like objects, so I imagine a generic solution would work. Answer Adding ChrisJY’s idea

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