On Sun, Dec 15, 2019 at 6:40 AM David Mertz <mertz@gnosis.cx> wrote:

Yes, of course. I was just trying to illustrate using next() in a non-artificial way. In real code (but truthfully, probably not in my quick "one off" scripts) I write

lines = get_lines_file_or_elswhere(resource)

header = next(lines, sentinel)

if looks_like_header(header):

    for line in lines:

        ...

Hmm, interesting -- so this means that you do write code expecting a generic iterator, rather than a file-like object.

I can't say I've ever done that, nor seem anyone else to that.

I'm curious: what other iterators might this code be expected to work with? (that is, a list of lines, as returned by file.readlines() would not work --you'd have to wrap it in iter() first...

I do this a lot for test cases. Instead of having a test file, I just have a list of lines that would be in the file, and pass that list in to a function that just takes an iterator. The function normally is passed a file, but also works for my test code which doesn't use files.

Eric