# Byte arrays

**URL:** <https://rubytalk.org/t/byte-arrays/11061>\
**Category:** ruby-talk\
**Created:** [18 April 2004 06:49 UTC](https://rubytalk.org/t/byte-arrays/11061 "2004-04-18T06:49:10Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![daz](https://avatars.discourse-cdn.com/v4/letter/d/87869e/32.png) [@daz](https://rubytalk.org/u/daz)\
**Post date:** [18 April 2004 06:49 UTC](https://rubytalk.org/t/byte-arrays/11061/1 "2004-04-18T06:49:10Z")

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Jeff Massung wrote:

> Sorry for [what is probably] a very newbie question, but is there any way  
> to specify just a straight byte array in Ruby? I want to just be able to  
> write the array directly to a binary file, but using regular ints will (I’m  
> assuming) write 32-bit values, and not bytes.
> 
> I’m sure there is a very simple way to do what I want (probably just using  
> the IO class), but I haven’t seen a writebytes or similar function yet. I’d  
> even consider using strings if needed.
> 
> Thanks.
> 
> –  
> Best regards,  
> Jeff Massung jma[at][mfire.com](http://mfire.com)  
> [http://www.jm-basic.com/](http://www.jm-basic.com/)

IO#putc writes Fixnums etc. as 8-bit values.

> **···**
>
> #--------------------------------------  
> File.open(‘wbtest.txt’, ‘wb’) do |wbf|  
> ba = [‘A’, 66, ‘Chop’, ?D, “\n”]  
> ba.each {|b| wbf.putc b}  
> wbf.write(“END\n”)  
> end
> 
> File.open(‘wbtest.txt’, ‘rb’) { |wbf| p wbf.read } # Check what’s there
> 
> #=\> “ABCD\nEND\n”  
> #--------------------------------------
> 
> # Add new IO method ??
> 
> # 
> 
> # class IO
> 
> # def writebytes(arr)
> 
> # arr.each {|b| putc b}
> 
> # end
> 
> # end
> 
> # 
> 
> # wbf.writebytes(ba)
> 
> daz