[Numpy-discussion] Fromfile Issue

Nicola Creati ncreati@inogs...
Fri Mar 9 07:53:46 CST 2012


Il 09/03/2012 14:33, Warren Weckesser ha scritto:
>
>
> On Fri, Mar 9, 2012 at 7:26 AM, Nicola Creati <ncreati@inogs.it 
> <mailto:ncreati@inogs.it>> wrote:
>
>     Hello,
>     I'm writing a library able to read LAS lidar files. I generally
>     use it under Linux without any problems. I'm now testing my
>     library on a Windows 7 64 bit computer and I meet some problems
>     reading the file. I generally use fromfile function to read the
>     file. I noted that the fromfile returns an arry with some zeros at
>     the end if I read the whole file or if i read only a finite number
>     of data i get only a fraction of them. By the way I have created a
>     sample script that reproduces the problem I noted:
>
>     """ Sample code """
>     import numpy as np
>
>     sz = 1000000
>     data = np.random.random(sz)
>
>     output = open('test.bin', 'w')
>     data.tofile(output)
>     output.close()
>     del output
>
>     print 'Original data:', data
>
>     fid = open('test.bin', 'r')
>     new_data = np.fromfile(fid)
>     fid.close()
>     del fid
>     print 'Data read:',  new_data
>
>     fid = open('test.bin', 'r')
>     slice = np.fromfile(fid, count=100)
>     fid.close()
>     print '100 read data:',  slice
>
>
>     The "new_data" array has several zeros at the end. The "slice"
>     array has not 100 items. At every code run the "slice" array size
>     changes.
>
>     I'm using numpy 1.6.1 64bit (taken from Christoph Gohlke website)
>     , with python 2.7.2 64 bit.
>     Under Linux  Ubuntu 10.10 64bit and numpy 1.6.1 the code works as
>     expected.
>     Thanks.
>
>     Nicola
>
>
>
> Use the binary mode ('wb' and 'rb') when you open the files.
>
> Warren
>
>
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>
>
>

Hello,
thank you, I did not know that on Window you must explicitly use 'rb' or 
'wb'.

Cheers.

Nicola


>
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