bartc wrote:
"Steven D'Aprano" <st...@remove-this-cybersource.com.au> wrote in
message news:02969972$0$20647$c3e8...@news.astraweb.com...
On Fri, 14 Aug 2009 18:25:45 -0700, Dr. Phillip M. Feldman wrote:
It seems as though Python is actually expanding range(2,n) into a list
of numbers, even though this is incredibly wasteful of memory. There
should be a looping mechanism that generates the index variable values
incrementally as they are needed.
Others have already pointed out to you that xrange() (for Python 2.x)
does what you want. In Python 3.x, the old range() is gone for good, and
xrange() renamed to just range().
It does seem rather worrying that whoever originally thought up Python
decided it would be a good idea to implement a simple 1 to N (or 0 to
N-1) for-loop by first creating an array of N consecutive integers!
Whoever? I am shocked! ;-)
They must have known Python was going to be slow anyway, but this
wouldn't have helped the speed any. Nor the memory consumption.
A for-loop, for iterating over a simple sequence, should be one of the
fastest things in the language.
[Presumably the internal code that created those consecutive integers
used a more conventional looping method...]
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