On Sun, Dec 15, 2019 at 6:40 AM David Mertz <[email protected]> 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...
But apparently it reflects the move that Python has been making toward
being all about iterators.
I think first() would be a help mostly to folks that DON'T think primarily
in terms of iterators. And frankly, I think that is a population Python
should strive to support.
For the record, I write a lot of code that looks like:
data_file = get_lines_file_(resource)
header = data_file.readline()
if looks_like_header(header):
for line in data_file:
...
That is, I'm always expecting a file-like object, rather than a generic
iterator. That may be because I developed habits long before files were
iterators....
BTW: this has been a REALLY LONG thread -- I think it's time for a concrete
proposal to be written up, sonce it appears we're not all clear on what
we're talking about. For my part I think a first() function would be nice,
an am open to a couple variations, so someone with a stronger opinion
should propose something.
Tim: what version do you have in mind?
-CHB
--
Christopher Barker, PhD
Python Language Consulting
- Teaching
- Scientific Software Development
- Desktop GUI and Web Development
- wxPython, numpy, scipy, Cython
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