I submitted a patch a little while ago, https://github.com/numpy/numpy/pull/3107, which gave the searchsorted function the ability to search arrays sorted in descending order. At the time my approach was to detect the sortorder of the array by comparing the first and last elements. This works pretty well in most cases, but fails in one notable case. After giving it some thought, I think the best way to add searching of descending arrays to numpy would be by adding a keyword to the searchsorted function. I wanted to know what you guys thought of this before updating the pr. I would like to add something like the following to numpy: A = [10, 9, 2, 1] np.searchsorted(A, 5, sortorder='descending') the other option would be to auto-detect the order, but then this case might surprise some users: A = [0, 0, 0] A = np.sort(A)[::-1] print np.searchsorted(A, [1, -1]) # [3, 0] This might surprise a user who expects to be searching a descending array Bago
On Mon, May 6, 2013 at 6:54 PM, Bago <mrbago@gmail.com> wrote:
I submitted a patch a little while ago, https://github.com/numpy/numpy/pull/3107, which gave the searchsorted function the ability to search arrays sorted in descending order. At the time my approach was to detect the sortorder of the array by comparing the first and last elements. This works pretty well in most cases, but fails in one notable case. After giving it some thought, I think the best way to add searching of descending arrays to numpy would be by adding a keyword to the searchsorted function. I wanted to know what you guys thought of this before updating the pr.
I would like to add something like the following to numpy:
A = [10, 9, 2, 1] np.searchsorted(A, 5, sortorder='descending')
the other option would be to auto-detect the order, but then this case might surprise some users:
A = [0, 0, 0] A = np.sort(A)[::-1] print np.searchsorted(A, [1, -1]) # [3, 0]
This might surprise a user who expects to be searching a descending array
I agree, that result would not really be acceptable (could easily break various algorithms in very hard to notice cases), so a kwarg would be better. -n
On Mon, May 6, 2013 at 7:16 PM, Nathaniel Smith <njs@pobox.com> wrote:
I submitted a patch a little while ago, https://github.com/numpy/numpy/pull/3107, which gave the searchsorted function the ability to search arrays sorted in descending order. At the time my approach was to detect the sortorder of the array by comparing
first and last elements. This works pretty well in most cases, but fails in one notable case. After giving it some thought, I think the best way to add searching of descending arrays to numpy would be by adding a keyword to
On Mon, May 6, 2013 at 6:54 PM, Bago <mrbago@gmail.com> wrote: the the
searchsorted function. I wanted to know what you guys thought of this before updating the pr.
I would like to add something like the following to numpy:
A = [10, 9, 2, 1] np.searchsorted(A, 5, sortorder='descending')
the other option would be to auto-detect the order, but then this case might surprise some users:
A = [0, 0, 0] A = np.sort(A)[::-1] print np.searchsorted(A, [1, -1]) # [3, 0]
This might surprise a user who expects to be searching a descending array
I agree, that result would not really be acceptable (could easily break various algorithms in very hard to notice cases), so a kwarg would be better.
-n
+1 on kwarg approach.
participants (3)
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Bago -
Benjamin Root -
Nathaniel Smith