[Numpy-discussion] Extract Indices of Numpy Array Based on Given Bit Information

Artur Bercik vbubbly21 at gmail.com
Sat Oct 18 08:14:14 EDT 2014


On Sat, Oct 18, 2014 at 9:00 PM, Artur Bercik <vbubbly21 at gmail.com> wrote:

>
>
> On Sat, Oct 18, 2014 at 8:28 PM, Julian Taylor <
> jtaylor.debian at googlemail.com> wrote:
>
>> On 18.10.2014 07:58, Artur Bercik wrote:
>> > Dear Python and Numpy Users:
>> >
>> > My data are in the form of '32-bit unsigned integer' as follows:
>> >
>> > myData = np.array([1073741824, 1073741877, 1073742657, 1073742709,
>> > 1073742723, 1073755137, 1073755189,1073755969],dtype=np.int32)
>> >
>> > I want to get the index of my data where the following occurs:
>> >
>> > Bit No. 0–1
>> > Bit Combination: 00
>> >
>> > How can I do it? I heard this type of problem first time, please help
>> me.
>> >
>> > Artur
>> >
>>
>> not sure I understand the problem, maybe this?
>>
>> np.where((myData & 0x3) == 0)
>>
>
> yes, it works greatly for the following case:
>
> myData = np.array([1073741824, 1073741877, 1073742657, 1073742709,
> 1073742723, 1073755137, 1073755189,1073755969],dtype=np.uint32)
> Bit No. 0–1
> Bit Combination: 00
>
> Can you make such automation for the following case as well?
>
> Bit No. 2–5
> Bit Combination: 1101
>
> Thanks in the advance.
>

Also wondering why np.where((myData & 0x3) == 0) instead of just
np.where((myData
& 3) == 0)

>
>
>
>
>
>>
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