Does array.read() move file pointer automatically?
lionel.keene at gmail.com
Thu Feb 5 00:37:11 CET 2009
On Feb 4, 3:10 pm, MRAB <goo... at mrabarnett.plus.com> wrote:
> Lionel wrote:
> > Hello everyone. Quick question: When using the "read()" method in the
> > array module, must I redirect the current file pointer or will that
> > occur automatically?
> > For example, if I were to sequentially read data in chunks from a
> > binary file as in:
> > for currentChunk in range(numberOfChunksToRead):
> > floatData = array.array('f')
> > floatData.read(MyFileHandle, numberOfFloatsPerChunk)
> > ...go to work on data...
> > at each iteration of the "for" loop, will the next chunk of bytes be
> > read into "floatData" or must I move the file pointer by calling "seek
> > ()" or some function like that?
> The read() method has been deprecated since version Python 1.5.1. Use
> the fromfile() method instead.
> It will advance the file pointer.
Thank you, I'll change it. On a related matter, I seem to be making a
mistake somewhere in the way I'm importing and using modules (in
particular the "array" module).
The following code generates an error (traceback message follows
from numpy import *
def __init__(self, initialData):
test = array.array('f') # Trigger error message
The traceback message is:
test = array.array('f')
AttributeError: 'builtin_function_or_method' object has no attribute
According to the Python 2.5 documentation for the "array" module it
does have an "array" method. I'm closely following examples I've found
online (here, for ex: http://www.python.org/search/hypermail/python-1993/0393.html)
but don't see my error.
This error goes away if I change the import statement to:
from array import *
from numpy import *
and the instruction to
test = array('f')
but then I get another error (sorry I don't have it handy) that
implies Python is interpreting the object returned from "array('f')"
as a numpy.ndarray object. Something I'm doing is causing ambiguity it
Anyone? As always, thank you for the help.
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