Turn Dictionary of Lists into a 1D Numpy Array

If you're looking for a flat 1d array, you could just use np.concatenate:

>>> d = {'a': [1, 2, 3, 4, 5], 'b': [1, 2, 3, 4, 5], 'c': [1, 2, 3, 4, 5]}
>>> np.concatenate(list(d.values()))
array([1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5])

try this

list(my_dict.values())

(commentary added)

dict.values() returns view not a list. Refer here

from itertools import chain
import numpy as np
chn = chain.from_iterable(d.values())
np.array(list(chn))

Allocate numpy arrays ahead of time:

my_dict = {0:[0,3,2,1], 1:[4,2,1,3], 2:[3,4,2,1]}
array = numpy.ndarray((len(my_dict), len(my_dict.values()[0]))

then you can insert them into the array like so:

for index, val in enumerate(my_dict.values()):
    arr[index] = val
>>> arr
array([[ 0.,  3.,  2.,  1.],
       [ 4.,  2.,  1.,  3.],
       [ 3.,  4.,  2.,  1.]])

In order to get an ordered concatenation based on the keys:

np.array([d[k] for k in sorted(d.keys())]).flatten()

if you don't need any order based on the keys, @Padraic Cunningham's approach was the fastest based on my timings here...