[Numpy-discussion] Question about bounds checking
Rich E
rjel@ceh.ac...
Mon Aug 10 10:08:27 CDT 2009
Dear all,
I am having a few issues with indexing in numpy and wondered if you could help
me out.
If I define an array
a = zeros(( 4))
a
array([ 0., 0., 0., 0.])
Then I try and reference a point beyond the bounds of the array
a[4]
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
IndexError: index out of bounds
but if I use the slicing format to reference the point I get
a[0:4]
array([ 0., 0., 0., 0.])
a[0:10]
array([ 0., 0., 0., 0.])
it returns a[ 0 : 3 ], with no error raised. If I then ask for the shape of the
array, I get
a.shape
(4,)
but if I use
a[0:3].shape
(3,)
which is one less than I would have expected.
a[0:4].shape
(4,)
This is numpy 1.2.1 on python 2.5
Thanks in advance for you help,
Rich
More information about the NumPy-Discussion
mailing list