Filter question: Use :filter operator

[Mohammad Rahmani]

Issue with :filter operator

1. The variable temTid refers to tiddler xx/temp/data,

2. Tiddler xx/temp/data in its text field stores the name of another tiddler called aiche.org

3. The tiddler  aiche.org has a field called url

I want to retrieve the url value as below

\define temTid()  xx/temp/data

<$list filter="[<tempTid>get[text]] :filter[get[url]]">

</$list>

The :filter doesn't work and the $list just returns the result of the first part  [<tempTid>get[text]]

What do you think? (all of them are dynamic and the value changes in different runs)

I know I can do this in two separate steps! But I am looking for a one step solution as above

- Explanation

• xx/temp/data (this is a tiddler)
• text:  aiche.org
•   aiche.org (this is a tiddler)
• text: some text
• url: http:/aiche.org/blog  

Best wishes

Mohammad

[Saq Imtiaz]

:filter does exactly that, it filters which titles from the previous run are included based on whether its run returns a value for that title or not.

I think what you want is [<tempTid>get[text]get[url]]

[Mohammad Rahmani]

On Fri, May 14, 2021 at 8:10 PM Saq Imtiaz <saq.i...@gmail.com> wrote:

:filter does exactly that, it filters which titles from the previous run are included based on whether its run returns a value for that title or not.

But I cannot get the result by :filter, have you tried the below filter?

<$list filter="[<tempTid>get[text]] :filter[get[url]]">

</$list>

 

I think what you want is [<tempTid>get[text]get[url]]

Thanks Saq! sometimes I forgot things may be these are sign of alzheimer!

[Saq Imtiaz]

You are misunderstanding the purpose of :filter.

It is used to include or exclude titles from the previous run, based on whether this filter run returns a result or not. The same principle as the filter[] operator for which I recommend reading the docs as they mostly apply here too: https://tiddlywiki.com/#filter%20Operator

 

<$list filter="[<tempTid>get[text]] :filter[get[url]]">

The first filter run says: get the text field from the tiddler whose title is in the variable tempTid

The second filter run says: exclude all titles from the previous run, if they do not have url field. 

:filter does NOT change the input titles, it only excludes or includes them in its output based on the result of its filter run.

 

[Saq Imtiaz]

Another way to explain it is that:

<$list filter="[<tempTid>get[text]] :filter[get[url]]">

</$list>

is equivalent to:

<$list filter="[<tempTid>get[text]]">

<$list filter="[<currentTiddler>get[url]!is[blank]]" variable="null">

</$list>

</$list>

[Mohammad Rahmani]

Saq,

 Many thanks for the clarification and I read the document again!

This example is great! but for me they return two different results! That was my confusion!

I have attached a JSON test both above solutions!

Please try at https://tiddlywiki.com/prerelease/

and let me know if you see what I mean?

[Saq Imtiaz]

I'm on a touch device and can't test what you posted but let me clarify my examples above to:

Another way to explain it is that:

<$list filter="[<tempTid>get[text]] :filter[get[url]]">

<<currentTiddler>>

</$list>

is equivalent to:

<$list filter="[<tempTid>get[text]]">

<$list filter="[<currentTiddler>get[url]!is[blank]]" variable="null">

<currentTiddler>>

</$list>

</$list>

[Mohammad Rahmani]

On Fri, May 14, 2021 at 10:39 PM Saq Imtiaz <saq.i...@gmail.com> wrote:

I'm on a touch device and can't test what you posted but let me clarify my examples above to:

Thank you Saq,

This second example shows the same result and both show the TITLE of the filter not url!

I got your point, it passes the title and keeps it by end! It does not return the value!

Thank you for calcification!

 

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