I should have given better context. I one only sorts the same field numeric,
one gets:
123
132
213
231
312
321
Which is correct given the list of whole numbers in question. The stable sort
allows one to then sort by char 3 of each, to get the result in the “compound”
sort below.
So am I missing something in all this?
Craig
> On Sep 5, 2023, at 10:29 AM, Craig Newman via use-livecode
> <use-livecode@lists.runrev.com> wrote:
>
> I may be simply misunderstanding…
>
> Since HC days, one could concatenate sort criteria using the “&” character,
> and obtain multiple stable sorts in one go. In LC as well, since given, in a
> field 1:
>
> 231
>
> 312
>
> 123
>
> 213
>
> 321
>
> 132
>
> and in a button somewhere:
>
> on mouseUp
>
> get fld 1
>
> sort it numeric by char 1 of each & char 3 of each
>
> answer it
>
> end mouseUp
>
> We get:
>
> 132
>
> 123
>
> 231
>
> 213
>
> 321
>
> 312
>
>
>
> Craig
>
>
>
>
>> On Sep 3, 2023, at 8:29 AM, matthias rebbe via use-livecode
>> <use-livecode@lists.runrev.com> wrote:
>>
>> Hello Mark,
>>
>> thanks for explanation and also for your solution. I will try.
>>
>> Maybe i should get my book "regular expressions" from Jeffrey E.F.Friedl
>> from the shelf and should finish reading it, so i could make use of regular
>> expressions in Livecode more often.
>>
>> Regards,
>> Matthias
>>
>>> Am 03.09.2023 um 11:49 schrieb Mark Waddingham via use-livecode
>>> <use-livecode@lists.runrev.com>:
>>>
>>> On 2023-09-03 10:26, panagiotis m via use-livecode wrote:
>>>> Hello Matthias,
>>>> I do not think that the syntax "sort <container> by sortKey1 and sortKey2"
>>>> is supported
>>>
>>> Heh technically it 'is' - and does do something but it won't be what you
>>> expected...
>>>
>>> So the syntax for sort in this case is:
>>>
>>> sort <container> by <expression>
>>>
>>> This works by iterating over the elements in <container>, passing each
>>> through the expression to generate a sort key list, sorting that list and
>>> then reordering the original list.
>>>
>>> Expressions can contain the boolean 'and' operator, so:
>>>
>>> sort <container> by X and Y
>>>
>>> Means that the sort key is evaluated as 'X and Y' for each element -
>>> meaning sort ends up sorting a list of 'true' and 'false' values.
>>>
>>> As Panos says, if you want to sort by separate fields with decreasing
>>> priority you need to do multiple sorts from least priority to most - this
>>> works because 'sort' is stable (if two elements compare the same, then the
>>> order of them in the output list is the same as the first).
>>>
>>> The alternative is to work out a sort expression which combines the two
>>> parts of the element you want to sort so that the sort keys sort in that
>>> order. This can be quite tricky, but (for example) - let's say your
>>> container has elements of the form:
>>>
>>> <section-number>,<sub-section-number>
>>>
>>> So you want things in the 'obvious' sorted order - then you could use:
>>>
>>> sort tSections ascending text by format("%08d%08d", item 1 of each, item 2
>>> of each)
>>>
>>> Here the sortkey is defined so that the text sort of the sort keys is that
>>> same as sorting first by sub-section number and then by section number.
>>>
>>> Warmest Regards,
>>>
>>> Mark.
>>>
>>> --
>>> Mark Waddingham ~ m...@livecode.com ~ http://www.livecode.com/
>>> LiveCode: Build Amazing Things
>>>
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>>
>>
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