Sorted list - how to change it

[Lad]

I have a sorted list for example [1,2,3,4,5] and I would like to change
it in a random way
e.g [2,5,3,1,4] or [3,4,1,5,2] or in any other way except being
ordered.
What is the best/easiest
way how to do it?

Thank you for help
L.

[Wolfram Kraus]

Re: Sorted list - how to change it

On 09.11.2006 10:52, Lad wrote:

I have a sorted list for example [1,2,3,4,5] and I would like to change
it in a random way
e.g [2,5,3,1,4] or [3,4,1,5,2] or in any other way except being
ordered.
What is the best/easiest
way how to do it?
>
Thank you for help
L.
>

use random.shuffel:

>>import random
>>x = [1,2,3,4,5]
>>random.shuffl e(x)
>>x

[1, 4, 2, 3, 5]

>>random.shuffl e(x)
>>x

[4, 2, 1, 3, 5]

see: http://docs.python.org/lib/module-random.html

HTH,
Wolfram

[Lad]

Re: Sorted list - how to change it


Wolfram Kraus wrote:

On 09.11.2006 10:52, Lad wrote:

I have a sorted list for example [1,2,3,4,5] and I would like to change
it in a random way
e.g [2,5,3,1,4] or [3,4,1,5,2] or in any other way except being
ordered.
What is the best/easiest
way how to do it?

Thank you for help
L.

use random.shuffel:
>

>import random
>x = [1,2,3,4,5]
>random.shuffle (x)
>x

[1, 4, 2, 3, 5]

>random.shuffle (x)
>x

[4, 2, 1, 3, 5]
>
see: http://docs.python.org/lib/module-random.html

Wolfram,
Thanks a lot for help
L.

[Marc 'BlackJack' Rintsch]

Re: Sorted list - how to change it

In <1163065969.593 970.165600@b28g 2000cwb.googleg roups.com>, Lad wrote:

I have a sorted list for example [1,2,3,4,5] and I would like to change
it in a random way
e.g [2,5,3,1,4] or [3,4,1,5,2] or in any other way except being
ordered.

lst = [1, 2, 3, 4, 5]
tmp = list(lst)
while lst == tmp:
random.shuffle( lst)

If you *really* want to be sure it's not sorted after shuffling. :-)

Ciao,
Marc 'BlackJack' Rintsch

[Tim Chase]

Re: Sorted list - how to change it

>I have a sorted list for example [1,2,3,4,5] and I would like to change

>it in a random way
>e.g [2,5,3,1,4] or [3,4,1,5,2] or in any other way except being
>ordered.
>What is the best/easiest
> way how to do it?

>
use random.shuffel:
>

>>>import random
>>>x = [1,2,3,4,5]
>>>random.shuff le(x)
>>>x

[1, 4, 2, 3, 5]

Just a caveat from past experience...wh ile the OP was talking
about lists, for future reference random.shuffle( ) chokes on
strings (and possibly tuples). It requires the ability to edit
the target/parameter in place...a functionality that strings
don't provide.

Thus, for a "word jumble" program I was playing with, you can't
just do

word = 'hello'
random.shuffle( word)

but rather you have to list'ify the word, shuffle it, then pack
it back together:

word = 'hello'
a = list(word)
random.shuffle( a)
word = ''.join(a)

I remember seeing discussion on the list at one point of a
MutableString class, which might be successfully passed to
random.shuffle( ) without hiccuping.

-tkc

[Marc 'BlackJack' Rintsch]

Re: Sorted list - how to change it

In <pan.2006.11.09 .10.05.13.35244 3@gmx.net>, Marc 'BlackJack' Rintsch
wrote:

lst = [1, 2, 3, 4, 5]
tmp = list(lst)
while lst == tmp:
random.shuffle( lst)

Argh, that fails if the list is empty or contains just one item.

lst = [1, 2, 3, 4, 5]
if len(lst) 1:
tmp = list(lst)
while lst == tmp:
random.shuffle( lst)

Ciao,
Marc 'BlackJack' Rintsch

[Christophe]

Re: Sorted list - how to change it

Lad a écrit :

I have a sorted list for example [1,2,3,4,5] and I would like to change
it in a random way
e.g [2,5,3,1,4] or [3,4,1,5,2] or in any other way except being
ordered.
What is the best/easiest
way how to do it?
>
Thank you for help
L.

Not accepting that the shuffle outputs the same list as entered would
make the random less random :)

[Nick Craig-Wood]

Re: Sorted list - how to change it

Tim Chase <python.list@ti m.thechases.com wrote:

Just a caveat from past experience...wh ile the OP was talking
about lists, for future reference random.shuffle( ) chokes on
strings (and possibly tuples). It requires the ability to edit
the target/parameter in place...a functionality that strings
don't provide.

You can always use array.array('c' ), eg

>>import random
>>import array
>>L = array.array('c' )
>>L.fromstring( "hello")
>>L

array('c', 'hello')

>>random.shuffl e(L)
>>L

array('c', 'elohl')

>>L.tostring( )

'elohl'

Which is some way towards a mutable string...

--
Nick Craig-Wood <nick@craig-wood.com-- http://www.craig-wood.com/nick