I'm using this sort of standard thing: for line in fileinput.input(): do_stuff(line) and wondering whether it reads until it hits an EOF and then passes lines (one at a time) into the variable line. This appears to be the behaviour when it's reading STDIN interactively (i.e. from the keyboard). As a test, I tried this: for line in fileinput.input(): print '**', line and found that it would print nothing until I hit Ctl-D, then print all the lines, then wait for another Ctl-D, and so on (until I pressed Ctl-D twice in succession to end the loop). Is it possible to configure this to pass each line of input into line as it comes? Thanks, Adam

On 2007-12-18, Jonathan Gardner wrote: >> As a test, I tried this: >> >> for line in fileinput.input(): >> print '**', line >> >> and found that it would print nothing until I hit Ctl-D, then print >> all the lines, then wait for another Ctl-D, and so on (until I pressed >> Ctl-D twice in succession to end the loop). > There is probably a 1024 byte buffer. Try filling it up and see if you > get something before you hit CTRL-D. Thanks; I'm looking into the buffering question. > It sounds like you want to write some kind of interactive program for > the terminal. Do yourself a favor and use curses or go with a full- > blown GUI. No, I'm really interested in reading the input from files! This just came up because I was trying to test the program by giving it no filename arguments and typing sample input.

On 2007-12-20, Tim Roberts wrote: >>As a test, I tried this: >> >> for line in fileinput.input(): >> print '**', line >> >>and found that it would print nothing until I hit Ctl-D, then print >>all the lines, then wait for another Ctl-D, and so on (until I pressed >>Ctl-D twice in succession to end the loop). > > Note that you are doing a lot more than just reading from a file here. This > is calling a function in a module. Fortunately, you have the source to > look at. > > As I read the fileinput.py module, this will eventually call > FileInput.next(), which eventually calls FileInput.readline(), which > eventually calls stdin.readlines(_bufsize). The default buffer size is > 8,192 bytes. OK, I think I've got this figured out! I'll keep using fileinput.input() for the normal case (reading from files named as arguments) and use sys.stdin.readline() for testing (reading from the keyboard, when no filenames are given). Thanks to you and Jonathan for your advice.