ValueError: The elements are 0-sized
Haven't been able to find any information on the web about this problem. I'm trying to read from a text file using numpy.
data = np.fromfile("C:\Users\Dan\Desktop\elements.txt",dtype=str,count=-1,sep=' ')
When I run this code I get this error:
ValueError: The elements are 0-sized.
I've never seen this error before, and a Google search didn't return any information about this error. Why is this error occurring, and how can I get around it?
EDIT: Here is an excerpt from the text file
1 Hydrogen 1.008 2 Helium 4.002602 3 Lithium 6.94 4 Beryllium 9.0121831 5 Boron 10.81 6 Carbon 12.011
You're probably better off using np.genfromtxt for text files; np.fromfile is better for binary files.
This gives the string array you originally seemed to be going for:
>>> np.genfromtxt('tmp.txt', dtype=str) array([['1', 'Hydrogen', '1.008'], ['2', 'Helium', '4.002602'], ['3', 'Lithium', '6.94'], ['4', 'Beryllium', '9.0121831'], ['5', 'Boron', '10.81'], ['6', 'Carbon', '12.011']], dtype='|S9')
And this gives you a record array that has flexible dtype:
>>> np.genfromtxt('tmp.txt', dtype=None) array([(1, 'Hydrogen', 1.008), (2, 'Helium', 4.002602), (3, 'Lithium', 6.94), (4, 'Beryllium', 9.0121831), (5, 'Boron', 10.81), (6, 'Carbon', 12.011)], dtype=[('f0', '<i8'), ('f1', 'S9'), ('f2', '<f8')])
But this is what I would do, using unpack allows you to assign to several variables:
>>> n, name, mass = np.genfromtxt('tmp.txt', dtype='S', unpack=True) >>> n = n.astype(int) >>> mass = mass.astype(float)