[Numpy-discussion] silently ignored size mismatch (bug??)

Neal Becker ndbecker2@gmail....
Mon Oct 1 12:51:13 CDT 2012


Sounds like I'm not the only one surprised then:

http://projects.scipy.org/numpy/ticket/2220

Matthew Brett wrote:

> Hi,
> 
> On Mon, Oct 1, 2012 at 9:04 AM, Pierre Haessig <pierre.haessig@crans.org>
> wrote:
>> Hi,
>>
>> Le 28/09/2012 21:02, Neal Becker a écrit :
>>> In [19]: u = np.arange (10)
>>>
>>> In [20]: v = np.arange (10)
>>>
>>> In [21]: u[v] = u
>>>
>>> In [22]: u[v] = np.arange(11)
>>>
>>> silence...
>> I've same behavior with my numpy 1.6.2.
>>
>> It indeed looks strange that the end of the data vector is dropped in
>> silence.
> 
> Same on numpy 1.4.1.  I also would have predicted an error in that
> situation.  For example in matlab:
> 
>>> a = 1:10
> 
> a =
> 
>      1     2     3     4     5     6     7     8     9    10
> 
>>> b = 1:10
> 
> b =
> 
>      1     2     3     4     5     6     7     8     9    10
> 
>>> a(b) = 11:20
> 
> a =
> 
>     11    12    13    14    15    16    17    18    19    20
> 
>>> a(b) = 11:21
> ???  In an assignment  A(I) = B, the number of elements in B and
>  I must be the same.
> 
> Is there any reason not to do that?
> 
> Best,
> 
> Matthew




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