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Re: Manually culling a list

  • To: mathgroup at smc.vnet.net
  • Subject: [mg115113] Re: Manually culling a list
  • From: Zach Bjornson <bjornson at stanford.edu>
  • Date: Fri, 31 Dec 2010 05:00:10 -0500 (EST)

Indeed, I only meant to demo the usage of Map@Composition with Dynamic 
and Checkbox. The obvious extension was to use Symbol or Unique, as you 
did, Bobby. Downside is that those methods leak new symbols each time 
they're used.

Here's a reusable function that does the same thing and removes the 
symbols after use. (Remove is kind of sloppy, with "Global`*$*".)

CullList[list_] :=
   Block[{t, selected = Table[Unique[], {i, Length@list}] (*Use Table 
instead of Unique[list] to enable easier use of Remove*)},
    t = DialogInput[
      DialogNotebook[{TableForm@
         Partition[Riffle[Map[Composition[Checkbox, Dynamic], selected], 
list], 2],
        Button["Finish", DialogReturn[Pick[list, selected]]]}]];
    Remove["Global`$*"];
    Return[t]];

Cheers,
Zach

On 12/30/2010 7:27 PM, DrMajorBob wrote:
> Actually, I don't think that does the job.
>
> a) When checking items in the "checks" list, you can't see the items 
> in "list" that you're selecting.
>
> b) It involves manually listing variables a, b, c... to match the 
> list, which isn't very flexible.
>
> c) You cannot run
>
> checks = Map[Composition[Checkbox, Dynamic], selected]
>
> a second time to create a different culled list or to cull it further.
>
> The following solves those problems:
>
> list = CharacterRange["A", "F"];
>
> Grid@{list,
>   checks = Map[Composition[Checkbox, Dynamic], Unique /@ list]}
>
> selected = checks /. {Checkbox -> Identity, Dynamic -> Identity}
>
> {True, False, True, False, False, True}
>
> cull1 = Pick[list, selected]
>
> {"A", "C", "F"}
>
> Partition[Riffle[list, selected], 2]
>
> {{"A", True}, {"B", False}, {"C", True}, {"D", False}, {"E",
>   False}, {"F", True}}
>
> To further cull the list:
>
> Grid@{cull1,
>   checks = Map[Composition[Checkbox, Dynamic], Unique /@ cull1]}
>
> selected = checks /. {Checkbox -> Identity, Dynamic -> Identity}
>
> {False, True, True}
>
> cull2 = Pick[cull1, selected]
>
> {"C", "F"}
>
> Partition[Riffle[cull1, selected], 2]
>
> {{"A", False}, {"C", True}, {"F", True}}
>
> Bobby
>
> On Thu, 30 Dec 2010 18:07:18 -0600, Zach Bjornson 
> <bjornson at stanford.edu> wrote:
>
>> Hi,
>>
>> In[1]:= list = CharacterRange["A", "F"]
>> Out[1]= {"A", "B", "C", "D", "E", "F"}
>>
>> In[2]:= selected = {a, b, c, d, e, f};
>>
>> In[3]:= checks = Map[Composition[Checkbox, Dynamic], selected]
>> Out[3]:= (*Checkboxes appear here*)
>>
>> In[4]:= culledlist = Dynamic@Pick[list, selected]
>>
>> Out[4]= (*Dynamic list of selected items appears here*)
>>
>> (*The list in the format you described*)
>> In[5]:= Partition[Riffle[list, selected], 2]
>> Out[5]= {{"A", True}, {"B", True}, {"C", True}, {"D", False}, {"E",
>>    True}, {"F", False}}
>>
>> Cheers,
>> Zach
>>
>> On 12/30/2010 1:10 AM, ntg wrote:
>>> Hello guys,
>>>
>>> Suppose I have a longish list of items that I want to manually cull.
>>> It seems I should be able to do something like
>>>
>>> checkList = ({Checkbox[], #)&  /@ list
>>>
>>> Then, I could write
>>>
>>> instanceOfCheckList = checkList
>>>
>>> check away, and hopefully see something like
>>>
>>> {{True, item1}, {False, item2}, ...}
>>>
>>> which I could manipulate. But all I see is the the list of "checked"
>>> checkboxs and items, not the consequence of checking the boxes. I can
>>> do a FullForm on instanceOfCheckList and extract what I need via list
>>> surgery-- but that is inelegant. I'm sure there is some magic
>>> incantation involving Evaluate or Interpretation or Dynamic. Can you
>>> help?
>>>
>>> Thanks,
>>> Tom
>>>
>>
>>
>
>


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