It was the first time I tried to create a structured array in numpy.
Usually I use pandas for heterogeneous arrays, but it is one more
dependency to my project.

It took me some time (really, much more than some), to understand the
problem with structured array creation. As example:

I had list of list of this kind:
b=[[ 1, 10.3, 12.1, 2.12 ],...]

And tried:
np.array(b, dtype='i4,f4,f4,f4')

Which raises some weird exception:
TypeError: a bytes-like object is required, not 'int'

Two hours later I found that I need list of tuples. I didn't find any help
in documentation and could not realize that the problem with the inner

Why there is such restriction - 'list of tuples' to create structured
array? What is the idea behind that, why not list of lists, or tuple of
lists or ...?

Also the exception does not help at all...
p.s.: It looks like that dtype also accepts only list of tuples. But I can
not catch the idea for this restrictions.
NumPy-Discussion mailing list

Reply via email to