Removing non Printable values aftert Encoding.ASCII.GetString()

Question

Suppose I have a Byte array and I use Encoding.ASCII.GetString() to convert the bytes into a string. Now the first few bytes will contain actual values, but the remaining ones will all have value of 0. After obtaining the string, when I show it on a WPF Form, there are some non printable characters. How can I remove these non printable characters. One way would be to loop through the array and only consider up to an index not containing 0, but I may also Encode using Unicode, that is Encoding.Unicode.GetString().

What would be the most generic way to solve the problem.

Do you know the actual encoding of the Byte array? I'm imagining the input array to be Chinese, UTF8 encoding, for example. — tofutim, Jun 02 '11 at 08:05
@tofutim: Yes, I know the actual encoding that is being used, but as I mentioned, it will vary from scenario to scenario. — Shamim Hafiz - MSFT, Jun 02 '11 at 08:06
Are you insuring for when the encoding is unknown and you choose ASCII? Converting from a foreign language could lead to diamonds and hearts, etc. Do you just mean to strip those weird ASCII non-characters like beeps? How about linefeeds and tabs? — tofutim, Jun 02 '11 at 08:08
@tofutim: There are no line feeds and tabs. It will be some characters and the remaining of the byte array will be zero. Had it been just ASCII Encoding, I would just look for first zero. — Shamim Hafiz - MSFT, Jun 02 '11 at 08:11

score 4 · Accepted Answer · answered Jun 02 '11 at 08:19

4

var buffer = new byte[] { 65, 66, 67, 68, 0, 0, 0, 0, 0 };
var length = buffer.TakeWhile(b => b != 0).Count();
var text = Encoding.UTF8.GetString(buffer, 0, length);

answered Jun 02 '11 at 08:19

Anthony Faull

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what if there was a character where the first bytes are 0? – Shamim Hafiz - MSFT Jun 02 '11 at 08:29
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In UTF-8 (and ASCII too) a zero byte is never part of a character. It can safety be used as a string terminator. – Anthony Faull Jun 02 '11 at 08:35
Thanks, just one note is TakeWhile defined in Visual Studio 2008? – Shamim Hafiz - MSFT Jun 02 '11 at 08:49
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Yes. TakeWhile is in the System.Linq namespace for .NET 3.5. – Anthony Faull Jun 02 '11 at 08:54
It didn't show up on Visual Studio auto-complete. I am declaring the type as byte[] and not var. Could this have something to do with that? In case, I ran a loop and your suggestion is working fine. – Shamim Hafiz - MSFT Jun 02 '11 at 08:56
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(1) At the top of your class file add "using System.Linq". (2) In Project Settings check that your .NET Framework version is 3.5 or above. (3) In Project References make sure "System.Core" appears. – Anthony Faull Jun 02 '11 at 09:24

score 0 · Answer 2 · answered Jun 02 '11 at 08:20

0

I'd just find the first zero in the array and strip off everything that follows.

answered Jun 02 '11 at 08:20

David Heffernan

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Removing non Printable values aftert Encoding.ASCII.GetString()

2 Answers2