Pytables Create_array Fails To Save Numpy Array

Why does the snipped below give: 'TypeError: Array objects cannot currently deal with void, unicode or object arrays'? Python 3.8.2, tables 3.6.1, numpy 1.19.1 import numpy as np i

Solution 1:

File.create_array() is for homogeneous dtypes (all ints, or all floats, etc). PyTables uses a different object to save mixed dytpes. You need to use File.create_table() instead. See modified code below (only the last line changed).

TYPE = np.dtype([ ('d', 'f4') ])
with tb.open_file(r'c:\temp\file.h5', mode="a") as h5file:
    h5file.create_group(h5file.root, 'grp')
    arr = np.array([(1.1)], dtype=TYPE)
    h5file.create_table('/grp', str('arr'), arr)

Note: you will get an error with mode='a' if you run with an existing temp.h5 file from your previous work. This is due to a conflict with group /grp created the first time.