On 6/20/10, Neil Thorman <neil.thor...@gmail.com> wrote: > I'm picking this up as a hobby really, not having done any programming since > Acorn I'm pretty much starting form scratch (and even back in the BASIC day > I never really got to grips with files). > This is from Alan Gauld's Learning to Program: Handling Files. > http://www.freenetpages.co.uk/hp/alan.gauld/ > > <http://www.freenetpages.co.uk/hp/alan.gauld/>Can I just check I'm getting > it? > > > *Menu.txt contains* > > *Spam & Eggs* > *Spam & Chips* > *Spam & Spam* > >>>>inp = file("menu.txt", "r") > *What is inp? What does it now contain?* It is now a reference to the location of the txt file. Python calls these file "objects", where an object is just something on which you can call functions. If you had a dog object you might call a "bark" method; here, we have a file object, so we can see what the file is. inp is not the file itself, just as any object is not the full object's info but rather a pointer to where that info is. If you were to print inp, I think you would get a memory address. > *The following creates a list;* > * > * > * >>>>print inp.readlines() > ['spam & eggs\n', 'spam & chips\n', 'spam & spam'] > > but if I do it again I get: >>>> print inp.readlines() > [] > > I'm baffled, why is inp now empty? I suspect you have hit the end of the file. I rarely work with files myself, but I believe there is a way to reset your pointer in the file to the top; after the readlines call, that pointer is at the end of the file. > > Many thanks > > Neil > > ps. I'm working in the IDLE Python Shell. > * > * > * > * > * > * > * > * > * > > > This email is confidential and intended for addressee only . >
-- Have a great day, Alex (msg sent from GMail website) mehg...@gmail.com; http://www.facebook.com/mehgcap _______________________________________________ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
