Read Binary data

[Mars creature]

Hi guys,
I am trying to read a binary file created by the following matlab
command:
fid=fopen('a.bi n','w','b'); fwrite(fid,a,'r eal*8'); fclose(fid);, and
wondering how to do it in Python. I googled it but still get
confused.
'b' in fopen is for 'big-endian', 'real*8' in fwrite is for 64bit
float.
Thank you very much!
Jinbo Wang

[Fredrik Lundh]

Re: Read Binary data

"Mars creature" wrote:

I am trying to read a binary file created by the following matlab
command:
fid=fopen('a.bi n','w','b'); fwrite(fid,a,'r eal*8'); fclose(fid);, and
wondering how to do it in Python. I googled it but still get
confused.
'b' in fopen is for 'big-endian', 'real*8' in fwrite is for 64bit
float.

f = open("a.bin", "rb") # read binary data
s = f.read() # read all bytes into a string

import array, sys

a = array.array("f" , s) # "f" for float
if sys.byteorder != "big":
a.byteswap()

</F>

[Mars creature]

Re: Read Binary data

On Sep 4, 12:03 pm, Fredrik Lundh <fred...@python ware.comwrote:

"Mars creature" wrote:

I am trying to read a binary file created by the following matlab
command:
fid=fopen('a.bi n','w','b'); fwrite(fid,a,'r eal*8'); fclose(fid);, and
wondering how to do it in Python. I googled it but still get
confused.
'b' in fopen is for 'big-endian', 'real*8' in fwrite is for 64bit
float.

>
f = open("a.bin", "rb") # read binary data
s = f.read() # read all bytes into a string
>
import array, sys
>
a = array.array("f" , s) # "f" for float
if sys.byteorder != "big":
a.byteswap()
>
</F>

Thanks Fredrik! I appreciate it!
The only thing is that a = array.array("f" , s) should be a =
array.array("d" , s) as the data is double precision.
Thanks again!

[mblume]

Re: Read Binary data

Am Thu, 04 Sep 2008 18:03:54 +0200 schrieb Fredrik Lundh:

>

> I am trying to read a binary file [...]

>
>
f = open("a.bin", "rb") # read binary data
s = f.read() # read all bytes into a string
>
import array, sys
>
a = array.array("f" , s) # "f" for float
if sys.byteorder != "big":
a.byteswap()
>

For more complicated structures, the struct module may help.

HTH.
Martin