How to parse bitstring?

Questions / Help
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1

Hi,

Anyone know how to parse a bitstring?
I have values like this : <<170, 192, 65, 0, 100, 0, 61, 86, 56, 171>> coming in from a sensor.
I need to get 65 ad 100 out to of that without changing them to another number. Anyone have an idea as to how to do that?

Thanks

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2

Something like this:

iex> x = <<170, 192, 65, 0, 100, 0, 61, 86, 56, 171>>
iex> << _ :: bytes-4, onehundred :: bytes-1, _ :: bytes-1, sixtyone :: bytes-1, _rest :: binary >> = x          
<<170, 192, 65, 0, 100, 0, 61, 86, 56, 171>>
iex> onehundred
"d"
iex> sixtyone
"="

This assumes you want the fields as binaries. If you want them as integers:

iex> << _ :: bytes-4, onehundred :: size(8), _ :: bytes-1, sixtyone :: size(8), _rest :: binary >> = x
<<170, 192, 65, 0, 100, 0, 61, 86, 56, 171>>
iex> sixtyone
61
iex> onehundred
100
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3

I’m sorry If I wasn’t clear.

When I said I wanted to get 65 I mean literally a “65” from that bitstring.
As in I want a list of all of the number values.

Ex:
a = <<170, 192, 65, 0, 100, 0, 61, 86, 56, 171>>
b = some_function(a)
b == [170, 192, 65, 0, 100, 0, 61, 86, 56, 171]

4

Here you go:

iex> :binary.bin_to_list x
[170, 192, 65, 0, 100, 0, 61, 86, 56, 171]
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5

Is this from the Erlang library?

6

Yes, it is. Everything in Erlang is available in Elixir.

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