Re: [IronPython] How to convert a 'str' type to byteArray

2009-11-12 Thread matan keret 
Thank you all for your help!

i tried the buffer idea, but it gave me a 'buffer' type and not a byteArray.
so i tried Michael's idea, which gave me some error. but then I found this
post: http://www.smallshire.org.uk/sufficientlysmall/tag/ironpython/

I fixed the code to:
from System import Array, Byte
a = Array[Byte](tuple(Byte(ord(c)) for c in image))

which seems to work :-)

Like Tony said, Thanks a lot for the info!



On Thu, Nov 12, 2009 at 6:21 AM, Toni Alatalo ant...@kyperjokki.fi wrote:

 Vernon Cole kirjoitti:

 Make sure what data type is really being returned by part.getpayload() .
  Perhaps it is already in a suitable for when you get it?


 Before he posted to the list we actually talked about this on irc too, and
 it seemed that it was unicode. He was seeing type 'str', but it seemed that
 str is unicode on ironpy, so probably that's why giving it to create a byte
 array doesn't work.

 s = 'this is a string'
 b = buffer(s)
 stores strings in unicode, and buffer() tries to be smart about hiding
 that fact, in order to act like CPython in the easy cases.  The above will
 work the same in either IronPython or CPython.


 Ok, AFAIK he wasn't trying buffer() yet and I also didnt't know much about
 it, so perhaps this is it? I'm sure he'll try soon.


 (IronPython seems to store them internally in UTF-8 or some similar code.)
  To convert to proper 8-bit codes you must use something like:
 u = u'unicode string'
 b = buffer(u.encode('latin-1'))


 The string/bytes is an image from an email (using some .net lib i guess,
 dunno on what that getpayload() is), I wonder if something like 'latin-1' is
 still the thing to use :o


 Python 3.x removes the problem by defining all character strings as unicode
 (as IronPython does now), and providing a byte() function, in which each 8
 byte is treated as an integer, rather than a character. That will make
 things simpler in the future.


 Indeed, perhaps the main reason why am looking forward to living in that
 land eventually.

 Thanks for info! (I and the OP work in the same overall project (
 http://www.realxtend.org/ open source virtual worlds / network games
 plat), even though I'm not working on the same thing he is now (we use
 ironpy on the server and cpython on the client, I'm mostly busy with the
 client side right now)

 VC


 ~Toni


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[IronPython] How to convert a 'str' type to byteArray

2009-11-11 Thread matan keret 
hi,

I have the following code which gets an image from an email.
after getting it i need to pass it as a byteArray (byte[] in C#) to a C#
function.
i tried all sorts of things but no luck. I'm using ironPython 2.0.3

the important parts of the code are:

# getting the image from the e-mail
image = part.get_payload()

# my try to cast the str into a byteArray
byteArray = BitConverter.GetBytes(image.ToCharArray())


this last line returns 1 byte and doesn't seem to do the job.
is there any equivalent to the 'bytearray(image)' function in CPython?

thanks,
Matan
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Re: [IronPython] How to convert a 'str' type to byteArray

2009-11-11 Thread Michael Foord 

matan keret wrote:

hi,
 
I have the following code which gets an image from an email.
after getting it i need to pass it as a byteArray (byte[] in C#) to a 
C# function.

i tried all sorts of things but no luck. I'm using ironPython 2.0.3
 
the important parts of the code are:
 
# getting the image from the e-mail

image = part.get_payload()
 
# my try to cast the str into a byteArray

byteArray = BitConverter.GetBytes(image.ToCharArray())
 
 
this last line returns 1 byte and doesn't seem to do the job.

is there any equivalent to the 'bytearray(image)' function in CPython?


I have no idea about the *specific* APIs you mention, but you can turn a 
string into a byte array with code like this (ignoring encoding issues):


   from System import Array, Byte

   byteArray = Array[Byte](ord(c) for c in some_string)

HTH!

Michael


 
thanks,

Matan
 



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Re: [IronPython] How to convert a 'str' type to byteArray

2009-11-11 Thread Vernon Cole 
Make sure what data type is really being returned by part.getpayload() .
Perhaps it is already in a suitable for when you get it?

The Python 2.x language method of loading a binary blob of memory is to use
the built in function buffer

s = 'this is a string'
b = buffer(s)

b will be accepted my a byte arrary in most cases.

but make sure that what you have is a legal ASCII string.  CPython stores
strings in ASCII and unicode differently. Iron Python stores strings
in unicode, and buffer() tries to be smart about hiding that fact, in order
to act like CPython in the easy cases.  The above will work the same in
either IronPython or CPython.

On the other hand, in CPython:
u =  u'this is a unicode string'
b = buffer(u)
will produce a blob twice (or four times) as long as the above, since it
stores all 16 (or 32) bits of  the character code.
(IronPython seems to store them internally in UTF-8 or some similar code.)
To convert to proper 8-bit codes you must use something like:

u = u'unicode string'
b = buffer(u.encode('latin-1'))

Python 3.x removes the problem by defining all character strings as unicode
(as IronPython does now), and providing a byte() function, in which each 8
byte is treated as an integer, rather than a character. That will make
things simpler in the future.
--
VC



On Wed, Nov 11, 2009 at 8:14 AM, matan keret matan...@gmail.com wrote:

 hi,

 I have the following code which gets an image from an email.
 after getting it i need to pass it as a byteArray (byte[] in C#) to a C#
 function.
 i tried all sorts of things but no luck. I'm using ironPython 2.0.3

 the important parts of the code are:

 # getting the image from the e-mail
 image = part.get_payload()

 # my try to cast the str into a byteArray
 byteArray = BitConverter.GetBytes(image.ToCharArray())


 this last line returns 1 byte and doesn't seem to do the job.
 is there any equivalent to the 'bytearray(image)' function in CPython?

 thanks,
 Matan


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 Users mailing list
 Users@lists.ironpython.com
 http://lists.ironpython.com/listinfo.cgi/users-ironpython.com


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Re: [IronPython] How to convert a 'str' type to byteArray

2009-11-11 Thread Toni Alatalo 

Vernon Cole kirjoitti:
Make sure what data type is really being returned by part.getpayload() 
.  Perhaps it is already in a suitable for when you get it?


Before he posted to the list we actually talked about this on irc too, 
and it seemed that it was unicode. He was seeing type 'str', but it 
seemed that str is unicode on ironpy, so probably that's why giving it 
to create a byte array doesn't work.

s = 'this is a string'
b = buffer(s)
stores strings in unicode, and buffer() tries to be smart about 
hiding that fact, in order to act like CPython in the easy cases.  The 
above will work the same in either IronPython or CPython.


Ok, AFAIK he wasn't trying buffer() yet and I also didnt't know much 
about it, so perhaps this is it? I'm sure he'll try soon.


(IronPython seems to store them internally in UTF-8 or some similar 
code.)  To convert to proper 8-bit codes you must use something like:

u = u'unicode string'
b = buffer(u.encode('latin-1'))


The string/bytes is an image from an email (using some .net lib i guess, 
dunno on what that getpayload() is), I wonder if something like 
'latin-1' is still the thing to use :o


Python 3.x removes the problem by defining all character strings as 
unicode (as IronPython does now), and providing a byte() function, in 
which each 8 byte is treated as an integer, rather than a character. 
That will make things simpler in the future.


Indeed, perhaps the main reason why am looking forward to living in that 
land eventually.


Thanks for info! (I and the OP work in the same overall project 
(http://www.realxtend.org/ open source virtual worlds / network games 
plat), even though I'm not working on the same thing he is now (we use 
ironpy on the server and cpython on the client, I'm mostly busy with the 
client side right now)



VC


~Toni

On Wed, Nov 11, 2009 at 8:14 AM, matan keret matan...@gmail.com 
mailto:matan...@gmail.com wrote:


hi,
 
I have the following code which gets an image from an email.

after getting it i need to pass it as a byteArray (byte[] in C#)
to a C# function.
i tried all sorts of things but no luck. I'm using ironPython 2.0.3
 
the important parts of the code are:
 
# getting the image from the e-mail

image = part.get_payload()
 
# my try to cast the str into a byteArray

byteArray = BitConverter.GetBytes(image.ToCharArray())
 
 
this last line returns 1 byte and doesn't seem to do the job.

is there any equivalent to the 'bytearray(image)' function in CPython?
 
thanks,

Matan
 


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