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Math Forum » Discussions » Software » comp.soft-sys.math.mathematica

Topic: Group and Replace itens sequence in a list
Replies: 10   Last Post: Aug 29, 2012 1:14 AM

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Ulrich Arndt

Posts: 39
Registered: 10/1/09
Re: Group and Replace itens sequence in a list
Posted: Aug 23, 2012 8:52 PM
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This one requires no X

ls = ReplaceRepeated[l, {x___, a, b, a, y___} -> {{x}, {y}}]
Extract[ls, Position[ls, {a___?AtomQ}]]

Ulrich

Am 23.08.2012 um 08:52 schrieb Murta:

> Hi All
>
> I have a simple problem that is:
>
> l={1,2,3,a,b,a,4,5,6,a,b,c,7,8,9,a,b,a,10,11,12}
>
> I want to replace all a,b,a sequence by X to get:
>
> l={1,2,3,X,4,5,6,a,b,7,8,9,X,10,11,12}
>
> Then I want to group it by X intervals as
> l={{1,2,3},{4,5,6,a,b,7,8,9},{10,11,12}}
>
> If I don't need to put the intermediate X, even better!
> I think the with pattern, RaplaceAll and DeleteCases I can do It. Some clue?
> Tks
> Murta
>
>
>

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