# Variable type while creating a block **URL:** \ **Category:** GNU Radio\ **Created:** [June 16, 2015, 11:41pm UTC](https://www.ruby-forum.com/t/variable-type-while-creating-a-block/242343 "2015-06-16T23:41:32Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![Detlef\_R](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/58f4c7/32.png) [@Detlef\_R](https://www.ruby-forum.com/u/Detlef_R)\ **Post date:** [June 16, 2015, 11:41pm UTC](https://www.ruby-forum.com/t/variable-type-while-creating-a-block/242343/1 "2015-06-16T23:41:32Z")
Hello If i set the input of my block as a byte, means that the block will handle 8 bits at a time and each item correspond to one bit of that byte? in[0] is the first bit and so on? Thank you. – View this message in context: [http://gnuradio.4.n7.nabble.com/variable-type-while-creating-a-block-tp54226.html](http://gnuradio.4.n7.nabble.com/variable-type-while-creating-a-block-tp54226.html) Sent from the GnuRadio mailing list archive at [Nabble.com](http://Nabble.com). ---
**Author:** ![Marbellys](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/9fc348/32.png) [@Marbellys](https://www.ruby-forum.com/u/Marbellys)\ **Post date:** [June 17, 2015, 1:20am UTC](https://www.ruby-forum.com/t/variable-type-while-creating-a-block/242343/2 "2015-06-17T01:20:16Z")
On Tue, Jun 16, 2015 at 2:17 PM, Marbellys [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > If i set the input of my block as a byte, means that the block will handle > 8 > bits at a time and each item correspond to one bit of that byte? > > in[0] is the first bit and so on? No, this isn’t automatic. You would also have to precede your block with a block like gr::blocks::unpack\_k\_bits\_bb or ::repack\_k\_bits\_bb to generate such a stream from a packed byte format. ---
**Author:** ![Marbellys](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/9fc348/32.png) [@Marbellys](https://www.ruby-forum.com/u/Marbellys)\ **Post date:** [June 17, 2015, 1:36am UTC](https://www.ruby-forum.com/t/variable-type-while-creating-a-block/242343/3 "2015-06-17T01:36:38Z")
Thank you, Johnathan. So if i use an unpack\_k\_bits block, and i set k to 1, will I be handle 1 bit at a time? – View this message in context: [http://gnuradio.4.n7.nabble.com/variable-type-while-creating-a-block-tp54226p54229.html](http://gnuradio.4.n7.nabble.com/variable-type-while-creating-a-block-tp54226p54229.html) Sent from the GnuRadio mailing list archive at [Nabble.com](http://Nabble.com). ---
**Author:** ![Marbellys](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/9fc348/32.png) [@Marbellys](https://www.ruby-forum.com/u/Marbellys)\ **Post date:** [June 17, 2015, 4:06am UTC](https://www.ruby-forum.com/t/variable-type-while-creating-a-block/242343/4 "2015-06-17T04:06:11Z")
On Tue, Jun 16, 2015 at 4:13 PM, Marbellys [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > So if i use an unpack\_k\_bits block, and i set k to 1, will I be handle 1 > bit at a time? Yes. ---
**Author:** ![Marbellys](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/9fc348/32.png) [@Marbellys](https://www.ruby-forum.com/u/Marbellys)\ **Post date:** [June 17, 2015, 9:32am UTC](https://www.ruby-forum.com/t/variable-type-while-creating-a-block/242343/5 "2015-06-17T09:32:14Z")
Dear Marbelly, unpack\_k\_bits with k = 1 means, for instance, a byte sample 0x0F (0b0000 1111) in a stream is unpacked to 0x00 0x00 0x00 0x00 0x01 0x01 0x01 0x01 (MSB first) and only the first insignificant sample is taken and the rest 7 samples are discarded. So if you want to process 8 bits in a byte individually, use unpack\_k\_bits with k = 8. Regards, Jeon. 2015-06-17 11:49 GMT+09:00 Marbellys [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid): ---
**Author:** ![Marbellys](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/9fc348/32.png) [@Marbellys](https://www.ruby-forum.com/u/Marbellys)\ **Post date:** [June 17, 2015, 11:56pm UTC](https://www.ruby-forum.com/t/variable-type-while-creating-a-block/242343/6 "2015-06-17T23:56:51Z")
Hi Jeon. Thank you very much for your response. So if I have for example a vector source V = (1,1,0,1,0,0,1,0,0,0,1,0,1,1,0,1 (which output’s type is set to byte), the first stream at the output will be (1,1,0,1,0,0,1,0), is this right? Then, if I use an unpack\_k\_bits with k = 8 at its output, will I be able to save each of this bits in a vector in a new block and to manipulated them individually? Thank you. Marbellys. – View this message in context: [http://gnuradio.4.n7.nabble.com/variable-type-while-creating-a-block-tp54226p54253.html](http://gnuradio.4.n7.nabble.com/variable-type-while-creating-a-block-tp54226p54253.html) Sent from the GnuRadio mailing list archive at [Nabble.com](http://Nabble.com). ---
**Author:** ![Marbellys](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/9fc348/32.png) [@Marbellys](https://www.ruby-forum.com/u/Marbellys)\ **Post date:** [June 17, 2015, 5:13am UTC](https://www.ruby-forum.com/t/variable-type-while-creating-a-block/242343/7 "2015-06-17T05:13:26Z")
Thank you. – View this message in context: [http://gnuradio.4.n7.nabble.com/variable-type-while-creating-a-block-tp54226p54232.html](http://gnuradio.4.n7.nabble.com/variable-type-while-creating-a-block-tp54226p54232.html) Sent from the GnuRadio mailing list archive at [Nabble.com](http://Nabble.com).