[erlang-questions] Bitstring question

Karolis Petrauskas <>
Wed Feb 12 08:05:52 CET 2014


The "/bits" says, that the argument is bitstring.
The "0:2" says, its an integer who's size is 2 bits. And "0" here is
an integer, not a bitstring.

Karolis

On Wed, Feb 12, 2014 at 9:01 AM, Mike Oxford <> wrote:
> Thank you!
> But ...
>
> 64> <<0:2/bits, D/bits>>.
> ** exception error: bad argument
> 65> <<0:2, D/bits>>.
> <<"!">>
>
> ??  Why does explicitly qualifying the 0:2 with /bits cause it to fail?
>
>
>
>
>
>
> On Tue, Feb 11, 2014 at 10:41 PM, Karolis Petrauskas
> <> wrote:
>>
>> 1> D = <<33:6>>.
>> <<33:6>>
>> 3> E = <<0:2, D/bits>>.
>> <<"!">>
>> 5> <<F>> = E.
>> <<"!">>
>> 6> F.
>> 33
>>
>> Karolis
>>
>> On Wed, Feb 12, 2014 at 8:36 AM, Mike Oxford <> wrote:
>> > << 0:2, D >> should concat the two.  Erlang knows what D is.
>> > <<0:2/bits, D:6/bits>> should construct a single 8-bit value.
>> > <<D/integer>> should (IMO) be valid because the value (33) is within the
>> > range of /integer
>> >
>> > How would you convert it back out to 33?
>> >
>> >
>> > On Tue, Feb 11, 2014 at 10:32 PM, Dmitry Kolesnikov
>> > <>
>> > wrote:
>> >>
>> >> Hello,
>> >>
>> >> Please see comments inline.
>> >>
>> >> Best Regards,
>> >> Dmitry >-|-|-(*>
>> >>
>> >>
>> >> > On 12.2.2014, at 8.27, Mike Oxford <> wrote:
>> >> >
>> >> > D = <<33:6>>
>> >> > <<33:6>>
>> >> D is length 6 bit
>> >> >
>> >> > I want to convert that 6 bit value (33) into a numeric value.
>> >> >
>> >> > Why does <<0:2, D>> not work?
>> >> Type and size is not specified
>> >> > Why does <<0:2/bits, D:6/bits>> not work?
>> >> Expected size is 8 bits but your bit string is 6
>> >> > Why does <<D/integer>> not work?
>> >> Integer is 32bit
>> >>
>> >> >
>> >> > Thanks in advance!
>> >> >
>> >> >
>> >> >
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>> >> > 
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>> >
>> >
>> >
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>
>



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