I have a very simple query, and I'm trying to convert it into a NumPy array using the fromiter() function. However, I can't figure out why it's not working, or what the error below means. Any ideas?
import numpy as np
c.execute("SELECT video_id FROM video")
results = c.fetchall()
D = np.fromiter(results, dtype=float, count=-1)
ERROR: ValueError: setting an array element with a sequence.
import numpy as np
from itertools import chain
c.execute("SELECT video_id FROM video")
results = c.fetchall()
D = np.fromiter(chain.from_iterable(results), dtype=float, count=-1)
This should extract the values from the tuples in results.
As before, results returns tuples, so you will have to pull the value out of the tuple using itertools.imap, or your own iterable adapter.
results = itertools.imap(lambda t: t[0], results)
But I'm just guessing the index since I don't know what you are querying.
I'm not expert with MySQL, but it looks like results is ending up as a list where each element is a sequence, like results = [(foo, bar), (baz, bid)], and those items aren't valid numpy array values.
Make sure that each element of results is actually a float, and not, say, a float in a tuple.
