python: sorting

Question

hi im doing a loop so i could get dict of data, but since its a dict it's sorting alphabetical and not as i push it trought the loop ...

is it possible to somehow turn off alphabetical sorting?

here is how do i do that

data = {}
for item in container:
  data[item] = {}
  ...
  for key, val in item_container.iteritems():
    ...
    data[item][key] = val

whitch give me something like this

data = {
  A : { K1 : V1, K2 : V2, K3 : V3 },
  B : { K1 : V1, K2 : V2, K3 : V3 },
  C : { K1 : V1, K2 : V2, K3 : V3 }
}

and i want it to be as i was going throught the loop, e.g.

data = {
  B : {K2 : V2, K3 : V3, K1 : V1},
  A : {K1 : V1, K2 : V2, K3 : V3},
  C : {K3 : V3, K1 : V1, K2 : V2}
}

It only seems alphabetical by chance. If you add more strings to it, or other items, you'll see that it's not alphabetical at all. Dicts have no reliable order. — Thomas Wouters
– Thomas Wouters, Commented Apr 13, 2010 at 14:24

Tim Pietzcker · Accepted Answer · 2010-04-13 14:26:29Z

5

If you really need to use a dictionary and not a list, take a look at the new OrderedDict (Python 3.1, soon to be available in Python 2.7, too). This will preserve the order in which its items were added.

from collections import OrderedDict
data = OrderedDict()
for item in container:
  data[item] = OrderedDict()
  ...
  for key, val in item_container.iteritems():
    ...
    data[item][key] = val

answered Apr 13, 2010 at 14:26

Tim Pietzcker

337k59 gold badges520 silver badges572 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Daniel Stutzbach Over a year ago

I suggest you add a link to the package that provides OrderedDict for Python 2.4 through 2.6: pypi.python.org/pypi/ordereddict

Tim Pietzcker Over a year ago

Oh, great - I didn't know about that. Well, you have already added the link, not much left for me to do :)

Justin Ethier · Accepted Answer · 2010-04-13 14:22:47Z

3

You should not be relying on the sort order of data in a dict; since it is just a collection of key/value pairs, the ordering is not guaranteed by the underlying implementation and could change in a future version.

answered Apr 13, 2010 at 14:22

Justin Ethier

135k53 gold badges235 silver badges290 bronze badges

1 Comment

Justin Ethier Over a year ago

For more information, see: stackoverflow.com/questions/613183/…

Ofri Raviv · Accepted Answer · 2010-04-13 15:27:55Z

0

You can use a list of lists, instead of a dict of dicts. Each element would be a tuple of (key,value). Of course, this means you won't be able to retrieve elements by keys, but it will preserve order. I'm not sure if its a good idea, because I don't really know what you're trying to do, but its an option.

answered Apr 13, 2010 at 15:27

Ofri Raviv

24.9k3 gold badges59 silver badges55 bronze badges

Collectives™ on Stack Overflow

python: sorting

3 Answers 3

2 Comments

1 Comment

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

2 Comments

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related