Python convert tuple to array

Question

How can I convert at 3-Dimensinal tuple into an array

a = []
a.append((1,2,4))
a.append((2,3,4))

in a array like:

b = [1,2,4,2,3,4]

Your listing shows a list of tuples (vaguely 2D-ish) – jmetz Dec 17 '13 at 15:27 — jmetz, Dec 17 '13 at 15:27
How do i just get the first element ? like b = [1,2] – Samy Dec 17 '13 at 15:42 — Samy, Dec 17 '13 at 15:42
@Samy `b[:2]` gets [1,2] – Alvaro Fuentes Dec 17 '13 at 15:46 — Alvaro Fuentes, Dec 17 '13 at 15:46

score 35 · Accepted Answer · answered Dec 17 '13 at 15:24

35

>>> a = []
>>> a.append((1,2,4))
>>> a.append((2,3,4))
>>> [x for xs in a for x in xs]
[1, 2, 4, 2, 3, 4]

>>> import itertools
>>> list(itertools.chain.from_iterable(a))
[1, 2, 4, 2, 3, 4]

answered Dec 17 '13 at 15:24

falsetru

score 14 · Answer 2 · answered Dec 17 '13 at 15:40

14

The simple way, use extend method.

x = []
for item in a:
    x.extend(item)

answered Dec 17 '13 at 15:40

MGP

score 8 · Answer 3 · answered Dec 17 '13 at 15:30

8

If you mean array as in numpy array, you can also do:

a = []
a.append((1,2,4))
a.append((2,3,4))
a = np.array(a)
a.flatten()

answered Dec 17 '13 at 15:30

user1654183

3 Answers3