Dictionary sorting problem

[JerryB]

Hi,
I have a dictionary for counting ocurrences of strings in a document.
The dictionary looks like this:

'hello':135
'goodbye':30
'lucy':4
'sky':55
'diamonds':2398 43
'yesterday':4

I want to print the dictionary so I see most common words first:

'diamonds':2398 43
'hello':135
'sky':55
'goodbye':30
'lucy':4
'yesterday':4

How do I do this? Notice I can't 'swap' the dictionary (making keys
values and values keys) and sort because I have values like lucy &
yesterday which have the same number of occurrences.

Thanks.

[Irmen de Jong]

Re: Dictionary sorting problem

JerryB wrote:[color=blue]
> Hi,
> I have a dictionary for counting ocurrences of strings in a document.
> The dictionary looks like this:
>
> 'hello':135
> 'goodbye':30
> 'lucy':4
> 'sky':55
> 'diamonds':2398 43
> 'yesterday':4
>
> I want to print the dictionary so I see most common words first:
>
> 'diamonds':2398 43
> 'hello':135
> 'sky':55
> 'goodbye':30
> 'lucy':4
> 'yesterday':4
>
> How do I do this? Notice I can't 'swap' the dictionary (making keys
> values and values keys) and sort because I have values like lucy &
> yesterday which have the same number of occurrences.
>
> Thanks.
>[/color]

Don't try to 'swap' the dict, just sort a list based on the items in
the dict. Try this:

original= {
'hello':135,
'goodbye':30,
'lucy':4,
'sky':55,
'diamonds':2398 43,
'yesterday':4 }

items = sorted( (v,k) for (k,v) in original.iterit ems() )
items.reverse() # depending on what order you want
print items


The result is:
[(239843, 'diamonds'), (135, 'hello'), (55, 'sky'), (30, 'goodbye'), (4, 'yesterday'),
(4, 'lucy')]


--Irmen

[Jason Mobarak]

Re: Dictionary sorting problem

You can't sort dictionaries (as implemented by hash tables), they are
unordered data types, so by definition there's no way to force an order
on them.

http://en.wikipedia.org/wiki/Hash_tables

[Bengt Richter]

Re: Dictionary sorting problem

On Fri, 16 Sep 2005 21:42:40 +0200, Irmen de Jong <irmen.NOSPAM@x s4all.nl> wrote:
[color=blue]
>JerryB wrote:[color=green]
>> Hi,
>> I have a dictionary for counting ocurrences of strings in a document.
>> The dictionary looks like this:
>>
>> 'hello':135
>> 'goodbye':30
>> 'lucy':4
>> 'sky':55
>> 'diamonds':2398 43
>> 'yesterday':4
>>
>> I want to print the dictionary so I see most common words first:
>>
>> 'diamonds':2398 43
>> 'hello':135
>> 'sky':55
>> 'goodbye':30
>> 'lucy':4
>> 'yesterday':4
>>
>> How do I do this? Notice I can't 'swap' the dictionary (making keys
>> values and values keys) and sort because I have values like lucy &
>> yesterday which have the same number of occurrences.
>>
>> Thanks.
>>[/color]
>
>Don't try to 'swap' the dict, just sort a list based on the items in
>the dict. Try this:
>
>original= {
>'hello':135,
>'goodbye':30 ,
>'lucy':4,
>'sky':55,
>'diamonds':239 843,
>'yesterday': 4 }
>
>items = sorted( (v,k) for (k,v) in original.iterit ems() )
>items.reverse( ) # depending on what order you want
>print items
>
>
>The result is:
>[(239843, 'diamonds'), (135, 'hello'), (55, 'sky'), (30, 'goodbye'), (4, 'yesterday'),
>(4, 'lucy')]
>
>[/color]
or tell sorted what to do ;-)
[color=blue][color=green][color=darkred]
>>> original= {[/color][/color][/color]
... 'hello':135,
... 'goodbye':30,
... 'lucy':4,
... 'sky':55,
... 'diamonds':2398 43,
... 'yesterday':4 }[color=blue][color=green][color=darkred]
>>> list(sorted(ori ginal.iteritems (), None, lambda t:t[1], True))[/color][/color][/color]
[('diamonds', 239843), ('hello', 135), ('sky', 55), ('goodbye', 30), ('yesterday', 4), ('lucy',4)]

Regards,
Bengt Richter

[Duncan Booth]

Re: Dictionary sorting problem

Bengt Richter wrote:
[color=blue]
> or tell sorted what to do ;-)
>[color=green][color=darkred]
> >>> original= {[/color][/color]
> ... 'hello':135,
> ... 'goodbye':30,
> ... 'lucy':4,
> ... 'sky':55,
> ... 'diamonds':2398 43,
> ... 'yesterday':4 }[color=green][color=darkred]
> >>> list(sorted(ori ginal.iteritems (), None, lambda t:t[1], True))[/color][/color]
> [('diamonds', 239843), ('hello', 135), ('sky', 55), ('goodbye', 30),
> ('yesterday', 4), ('lucy',4)][/color]

or a slight variation on this theme which just gives you the keys in value
order rather than the tuples:
[color=blue][color=green][color=darkred]
>>> for k in sorted(original , key=original.ge t, reverse=True):[/color][/color][/color]
print k, original[k]


diamonds 239843
hello 135
sky 55
goodbye 30
yesterday 4
lucy 4

[Bengt Richter]

Re: Dictionary sorting problem

On 17 Sep 2005 11:01:41 GMT, Duncan Booth <duncan.booth@i nvalid.invalid> wrote:
[color=blue]
>Bengt Richter wrote:
>[color=green]
>> or tell sorted what to do ;-)
>>[color=darkred]
>> >>> original= {[/color]
>> ... 'hello':135,
>> ... 'goodbye':30,
>> ... 'lucy':4,
>> ... 'sky':55,
>> ... 'diamonds':2398 43,
>> ... 'yesterday':4 }[color=darkred]
>> >>> list(sorted(ori ginal.iteritems (), None, lambda t:t[1], True))[/color]
>> [('diamonds', 239843), ('hello', 135), ('sky', 55), ('goodbye', 30),
>> ('yesterday', 4), ('lucy',4)][/color]
>
>or a slight variation on this theme which just gives you the keys in value
>order rather than the tuples:
>[color=green][color=darkred]
>>>> for k in sorted(original , key=original.ge t, reverse=True):[/color][/color]
> print k, original[k]
>[/color]
Nice. I like the keyword usage too. Much clearer than my hastypaste ;-)
[color=blue]
>
>diamonds 239843
>hello 135
>sky 55
>goodbye 30
>yesterday 4
>lucy 4[/color]

Regards,
Bengt Richter