write in file with python

Question

I am searching for the easiest way to save an array in a file. For this I would want to use numpy.savetxt but the problem is that my array is composed of n columns (the number depends on what i ant to do) and it contains complex elements (x+yj). I know how to save it if there is one column and real elements but I don't know how to do.

Does anybody have an idea?

Sorry I'm not allowed to comment but have you looked at stackoverflow.com/questions/3685265/…. yay that actually worked as a comment — Snesticle
– Snesticle, Commented Mar 14, 2012 at 18:10
I red it but there is not a very short answer. In fact I want to write something like 'numpy.savetext('myfile',myarray,fmt=???)'. — PanAkry
– PanAkry, Commented Mar 14, 2012 at 18:20
Have you tried the examples I gave? I ran them in the interpreter so I know they work. Does the output have to be human readable? — strcat
– strcat, Commented Mar 14, 2012 at 18:22

strcat · Accepted Answer · 2012-03-14 18:13:22Z

2

You could pickle them:

>>> A = np.array([[1,2],[3,4+2j]])
>>> pickle.dump(A, open("out.pkl", "wb"))
>>> pickle.load(open("out.pkl", "rb"))
array([[ 1.+0.j,  2.+0.j],
       [ 3.+0.j,  4.+2.j]])

However, it would be better to use numpy.save and numpy.load, they're designed for this and will use a lot less space.

>>> np.save("out.npy", A)
>>> np.load("out.npy")
array([[ 1.+0.j,  2.+0.j],
       [ 3.+0.j,  4.+2.j]])

edited Mar 14, 2012 at 18:13

answered Mar 14, 2012 at 18:08

strcat

5,6632 gold badges31 silver badges31 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

PanAkry Over a year ago

I already tried this and the answer is 'Casting complex values to real discards the imaginary part fh.write(asbytes(format % tuple(row) + newline))'

strcat Over a year ago

numpy.savetxt gives that output, not numpy.save. The savetxt function produces human readable output, and it doesn't work for this.

rdchambers Over a year ago

+1 on numpy.save , if you're not going to use it outside of Python.

Collectives™ on Stack Overflow

write in file with python

1 Answer 1

3 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

3 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related