[Numpy-discussion] Memory usage of numpy-arrays

Christopher Barker Chris.Barker@noaa....
Thu Jul 8 17:19:12 CDT 2010

Sebastian Haase wrote:
> This might be better done "by hand", i.e. in standard (non numpy) python:
> nums = []
> for line in file("myTextFile.txt"):
>      fields = line.split()
>      nums.extend (map(float, fields))

if you know how big your array needs to be, you can pre-allocate it with:

np.empty() or np.ones()

Then fill it in as you read the file -- that will be as memory efficient 
as you can do it.

Another option:

I wrote a expendable array class in Python a while back, which turns out 
not to be faster than using a list, but it should be more memory 
efficient -- you might try it (enclosed).


Christopher Barker, Ph.D.

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