[Numpy-discussion] fromstring, tostring slow?

Christopher Barker Chris.Barker@noaa....
Tue Feb 13 15:38:47 CST 2007


Mark Janikas wrote:
> I am finding that directly packing numpy arrays into binary using the 
> tostring and fromstring methods

For starters, use fromfile and tofile, to save the overhead of creating 
an entire extra string.

fromfile is a function (as it is an alternate constructor for arrays):

numpy.fromfile()

ndarray.tofile() is an array method.

Enclosed is your test, including a test for tofile(), I needed to make 
the arrays much larger, and use time.time() rather than time.clock() to 
get enough time resolution to see anything, though if you really want to 
be accurate, you need to use the timeit module.

My results:
Using lists 0.457561016083
Using tostring 0.00922703742981
Using tofile 0.00431108474731

Another note: where is the data coming from -- there may be ways to 
optimize this whole process if we saw that.

-Chris



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Christopher Barker, Ph.D.
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