Slicing Arrays in this way

[Tobiah]

>>> elegant_solution([1,2,3,4,5,6,7,8,9,10])

[[1, 2], [3, 4], [5, 6], [7, 8], [9, 10]]

 

[Matimus]

elegant_solution([1,2,3,4,5,6,7,8,9,10])

[[1, 2], [3, 4], [5, 6], [7, 8], [9, 10]]

--

seq = range(1,11)
seq [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
zip( seq[0::2],seq[1::2] )

[(1, 2), (3, 4), (5, 6), (7, 8), (9, 10)]

if you _really_ need lists then...

map(list, zip( seq[0::2],seq[1::2] ))

[[1, 2], [3, 4], [5, 6], [7, 8], [9, 10]]

 

[John Machin]

elegant_solution([1,2,3,4,5,6,7,8,9,10])

[[1, 2], [3, 4], [5, 6], [7, 8], [9, 10]]

What is your definition of "elegant"? What about other dimensions of
code quality like "robust" and "fast"?

What have you tried?

Here's one possibility:
zip(source[::2], source[1::2])
[I'm presuming you won't be upset by getting tuples instead of lists]

 

[Tobiah]

elegant_solution([1,2,3,4,5,6,7,8,9,10])

[[1, 2], [3, 4], [5, 6], [7, 8], [9, 10]]

--

seq = range(1,11)
seq [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
zip( seq[0::2],seq[1::2] )

[(1, 2), (3, 4), (5, 6), (7, 8), (9, 10)]

if you _really_ need lists then...

map(list, zip( seq[0::2],seq[1::2] ))

[[1, 2], [3, 4], [5, 6], [7, 8], [9, 10]]

I had come up with:

[[a[x], a[x + 1]] for x in range(0, 10, 2)]

I was hoping for something a little more concise.
Something like

list[::2:2] if that existed.

 

[Tobiah]

elegant_solution([1,2,3,4,5,6,7,8,9,10])

[[1, 2], [3, 4], [5, 6], [7, 8], [9, 10]]

What is your definition of "elegant"? What about other dimensions of
code quality like "robust" and "fast"?

What have you tried?

Here's one possibility:
zip(source[::2], source[1::2])
[I'm presuming you won't be upset by getting tuples instead of lists]

I like it, and it fits my definition of elegant.

 

[Tobiah]

I'm a retard. Disregard.

 

[Steven D'Aprano]

elegant_solution([1,2,3,4,5,6,7,8,9,10])

[[1, 2], [3, 4], [5, 6], [7, 8], [9, 10]]

Wow! That's impressive. What version of Python are you using? When I try
it, I get this:

elegant_solution([1,2,3,4,5,6,7,8,9,10])

Traceback (most recent call last):
File "<stdin>", line 1, in <module>
NameError: name 'elegant_solution' is not defined

 

[John Machin]

elegant_solution([1,2,3,4,5,6,7,8,9,10])

[[1, 2], [3, 4], [5, 6], [7, 8], [9, 10]]

Wow! That's impressive. What version of Python are you using? When I try
it, I get this:

elegant_solution([1,2,3,4,5,6,7,8,9,10])

Traceback (most recent call last):
File "<stdin>", line 1, in <module>
NameError: name 'elegant_solution' is not defined

The OP has already confessed. Don't rub it in.

 

[Ian Clark]

Yeah, having an elegant_solution() function would solve soo many of my
problems.

Ian

 

[Michael Hoffman]

elegant_solution([1,2,3,4,5,6,7,8,9,10])

[[1, 2], [3, 4], [5, 6], [7, 8], [9, 10]]

That's not an array, it's a list. See the array module for arrays
(fixed-length, unlike variable-length lists).

 

[John Machin]

elegant_solution([1,2,3,4,5,6,7,8,9,10])

[[1, 2], [3, 4], [5, 6], [7, 8], [9, 10]]

That's not an array, it's a list. See the array module for arrays
(fixed-length, unlike variable-length lists).

You must have your very own definitions of "fixed-length" and
"unlike".

import array
fixed = array.array('b')
fixed.append(42)
fixed.extend([0, 1, 127])
fixed array('b', [42, 0, 1, 127])
fixed.append(2)
fixed array('b', [42, 0, 1, 127, 2])
fixed[2:4] = array.array('b', [8])
fixed array('b', [42, 0, 8, 2])

 

[James Stroud]

elegant_solution([1,2,3,4,5,6,7,8,9,10])

[[1, 2], [3, 4], [5, 6], [7, 8], [9, 10]]

Here's one I use:

def elegant_solution(alist):
i = iter(alist)
return [[j, i.next()] for j in i]


py> elegant_solution(range(14))
[[0, 1], [2, 3], [4, 5], [6, 7], [8, 9], [10, 11], [12, 13]]

James

 

[Steven D'Aprano]

The OP has already confessed. Don't rub it in.

Sorry, I sent my comment before I received his confession.

 

[Michael Hoffman]

elegant_solution([1,2,3,4,5,6,7,8,9,10])
[[1, 2], [3, 4], [5, 6], [7, 8], [9, 10]]

That's not an array, it's a list. See the array module for arrays
(fixed-length, unlike variable-length lists).

You must have your very own definitions of "fixed-length" and
"unlike".

Sorry, too much time spent with numarray arrays which are documented to
have immutable size.

 

[Tobiah]

elegant_solution([1,2,3,4,5,6,7,8,9,10])
[[1, 2], [3, 4], [5, 6], [7, 8], [9, 10]]

Wow! That's impressive. What version of Python are you using? When I try
it, I get this:

elegant_solution([1,2,3,4,5,6,7,8,9,10])

Traceback (most recent call last):
File "<stdin>", line 1, in <module>
NameError: name 'elegant_solution' is not defined

The OP has already confessed. Don't rub it in.

Well, my first post made perfect sense. My 'confession'
involved noticing that I had replied to one respondent
saying that I wanted something more concise, while
praising the aptness of the same solution to the next
poster. Lack of oxygen, I think.