On 8/16/10 11:10 PM, Steven D'Aprano wrote:
On Mon, 16 Aug 2010 22:56:20 -0500, Robert Kern wrote:
On 8/16/10 9:29 PM, Roy Smith wrote:
In article<i4cqg0$ol...@lust.ihug.co.nz>,
Lawrence D'Oliveiro<l...@geek-central.gen.new_zealand> wrote:
In message<roy-ee1b7f.21001716082...@news.panix.com>, Roy Smith wrote:
5) real intensity[160.0 : 30.0 : 0.01]
How many elements in that array?
a) 2999
b) 3000
c) neither of the above
c) neither of the above. More specifically, 13,001 (if I counted
correctly).
13000, actually. Floating point is a bitch.
[~/Movies]
|1> import numpy
[~/Movies]
|2> len(numpy.r_[160.0:30.0:-0.01])
13000
Actually, the answer is 0, not 13000, because the step size is given as
0.01, not -0.01.
import numpy
len(numpy.r_[160.0:30.0:-0.01])
13000
len(numpy.r_[160.0:30.0:0.01])
0
Roy wasn't using numpy/Python semantics but made-up semantics (following Martin
Gregorie's made-up semantics to which he was replying) which treat the step size
as a true size, not a size and direction. The direction is determined from the
start and stop parameters. It's an almost-reasonable design.
--
Robert Kern
"I have come to believe that the whole world is an enigma, a harmless enigma
that is made terrible by our own mad attempt to interpret it as though it had
an underlying truth."
-- Umberto Eco
--
http://mail.python.org/mailman/listinfo/python-list
