convert binary to float

[Mason]

I have tried and tried...

I'd like to read in a binary file, convert it's 4 byte values into
floats, and then save as a .txt file.

This works from the command line (import struct);

In [1]: f = open("test2.pc0 ", "rb")
In [2]: tagData = f.read(4)
In [3]: tagData
Out[3]: '\x00\x00\xc0@'

I can then do the following in order to convert it to a float:

In [4]: struct.unpack(" f", "\x00\x00\xc0@" )
Out[4]: (6.0,)

But when I run the same code from my .py file:

f = open("test2.pc0 ", "rb")
tagData = f.read(4)
print tagData

I get this (ASCII??):
„@

I only know how to work with '\x00\x00\xc0@' .

I don't understand why the output isn't the same. I need a solution
that will allow me to convert my binary file into floats. Am I close?
Can anyone point me in the right direction?

Thanks,
Mason

[George Sakkis]

Re: convert binary to float

On Jun 1, 3:55 pm, Mason <john.gerald.ma ...@gmail.comwr ote:

I have tried and tried...
>
I'd like to read in a binary file, convert it's 4 byte values into
floats, and then save as a .txt file.
>
This works from the command line (import struct);
>
    In [1]: f = open("test2.pc0 ", "rb")
    In [2]: tagData = f.read(4)
    In [3]: tagData
    Out[3]: '\x00\x00\xc0@'
>
I can then do the following in order to convert it to a float:
>
    In [4]: struct.unpack(" f", "\x00\x00\xc0@" )
    Out[4]: (6.0,)
>
But when I run the same code from my .py file:
>
    f = open("test2.pc0 ", "rb")
    tagData = f.read(4)
    print tagData
>
I get this (ASCII??):
„@

Remembering to put that struct.unpack() call in your module might
help ;-)

George

[Mason]

Re: convert binary to float

On Jun 1, 5:12 pm, George Sakkis <george.sak...@ gmail.comwrote:

On Jun 1, 3:55 pm, Mason <john.gerald.ma ...@gmail.comwr ote:
>
>
>

I have tried and tried...

>

I'd like to read in a binary file, convert it's 4 byte values into
floats, and then save as a .txt file.

>

This works from the command line (import struct);

>

In [1]: f = open("test2.pc0 ", "rb")
In [2]: tagData = f.read(4)
In [3]: tagData
Out[3]: '\x00\x00\xc0@'

>

I can then do the following in order to convert it to a float:

>

In [4]: struct.unpack(" f", "\x00\x00\xc0@" )
Out[4]: (6.0,)

>

But when I run the same code from my .py file:

>

f = open("test2.pc0 ", "rb")
tagData = f.read(4)
print tagData

>

I get this (ASCII??):
„@

>
Remembering to put that struct.unpack() call in your module might
help ;-)
>
George

Wow ... I did have it in there, but I forgot include it in my post.
Anyway, this works just fine:

f = open("test2.pc0 ", "rb")
tagData = f.read(4)
print struct.unpack(" f", tagData)

Thanks for waking me up George!

[Mason]

Re: convert binary to float

On Jun 1, 6:41 pm, Dennis Lee Bieber <wlfr...@ix.net com.comwrote:

On Sun, 1 Jun 2008 12:55:45 -0700 (PDT), Mason
<john.gerald.ma ...@gmail.comde claimed the following in
comp.lang.pytho n:
>

I have tried and tried...

>

I'd like to read in a binary file, convert it's 4 byte values into
floats, and then save as a .txt file.

>

This works from the command line (import struct);

>

In [1]: f = open("test2.pc0 ", "rb")
In [2]: tagData = f.read(4)
In [3]: tagData

>
Interpreter display of raw object name uses repr()
>

Out[3]: '\x00\x00\xc0@'

>

I can then do the following in order to convert it to a float:

>

In [4]: struct.unpack(" f", "\x00\x00\xc0@" )
Out[4]: (6.0,)

>

But when I run the same code from my .py file:

>

f = open("test2.pc0 ", "rb")
tagData = f.read(4)
print tagData

>
Display from a print statement uses str()
>

I get this (ASCII??):
„@

>
Probably not ASCII -- ASCII doesn't have that spanish (?) bottom row
quote... And a pair of null bytes don't take up screen space.
>

I only know how to work with '\x00\x00\xc0@' .

>

I don't understand why the output isn't the same. I need a solution
that will allow me to convert my binary file into floats. Am I close?
Can anyone point me in the right direction?

>
Why do you have to /see/ the byte representation in the first
place... just feed the four bytes to the struct module directly.
>
import struct
fin = open("test2.pc0 ", "rb")
tagFloat = struct.unpack(" f", fin.read(4))[0]
print tagFloat
--
Wulfraed Dennis Lee Bieber KD6MOG
wlfr...@ix.netc om.com wulfr...@bestia ria.com

HTTP://wlfraed.home.netcom.com/

(Bestiaria Support Staff: web-a...@bestiaria. com)
HTTP://www.bestiaria.com/

Thanks Dennis, I'm OK now. I just sort of dropped the ball for a
bit :).

Mason

[Mark Tolonen]

Re: convert binary to float

>"George Sakkis" <george.sakkis@ gmail.comwrote in message

>news:829b1e8 f-baac-4ff4-909b->b39df97a436c@d 45g2000hsc.goog legroups.com...
>On Jun 1, 3:55 pm, Mason <john.gerald.ma ...@gmail.comwr ote:

>I have tried and tried...
>>
>I'd like to read in a binary file, convert it's 4 byte values into
>floats, and then save as a .txt file.
>>
>This works from the command line (import struct);
>>
>In [1]: f = open("test2.pc0 ", "rb")
>In [2]: tagData = f.read(4)
>In [3]: tagData
>Out[3]: '\x00\x00\xc0@'
>>
>I can then do the following in order to convert it to a float:
>>
>In [4]: struct.unpack(" f", "\x00\x00\xc0@" )
>Out[4]: (6.0,)
>>
>But when I run the same code from my .py file:
>>
>f = open("test2.pc0 ", "rb")
>tagData = f.read(4)
>print tagData
>>
>I get this (ASCII??):
>„@

>
Remembering to put that struct.unpack() call in your module might
help ;-)
>
George

tagData still contains your data, but it is being displayed two different
ways. Consult the documentation about str() and repr().

-Mark