[REBOL] Re: sort/compare
From: carl:cybercraft at: 8-Nov-2002 10:10
On 07-Nov-02, guimond wrote:
> Hi
> I try to sort a series of blocks on the second element of the block
> which represents the age of individuals.
> rebol []
> person: make block! [ name age ]
> damien: make person [ "Damien" 20 ]
> fabien: make person [ "Fabien" 1 ]
> list-of-person: [ Damien Fabien ]
> age-comp: func [ a b ] [ (second a) < (second b) ]
> sort/compare list-of-person :age-comp
> Script Error: second expected series argument of type: series pair
> event money date object port time tuple any-function struct event
> ** Where: halt-view
> ** Near: probe second a
> The comparator function works though!
>>> age-comp Damien Fabien
> == false
> How can I sort my series on the age ?
> thanks for help!
Hi Philippe,
You were almost there. The...
list-of-person: [ Damien Fabien ]
will just be a block containing the words Damien & Fabien, not the
contents of the Damien and Fabien blocks, as can be seen at the REBOL
console...
>> list-of-person: [ Damien Fabien ]
== [Damien Fabien]
>> probe list-of-person
[Damien Fabien]
== [Damien Fabien]
Reducing the block will give you what (I assume) you want though...
>> person: make block! [ name age ]
== [name age]
>> damien: make person [ "Damien" 20 ]
== ["Damien" 20]
>> fabien: make person [ "Fabien" 1 ]
== ["Fabien" 1]
>> list-of-person: reduce [ Damien Fabien ]
== [["Damien" 20] ["Fabien" 1]]
Your sort function will then work...
>> age-comp: func [ a b ] [ (second a) < (second b) ]
>> sort/compare list-of-person :age-comp
== [["Fabien" 1] ["Damien" 20]]
Hope that helps.
--
Carl Read
