MathGroup Archive 2004

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: DeleteCases : several at once, conditions


"camerzone" <camerzone at yahoo.com> schrieb im Newsbeitrag
news:cd8b1n$olb$1 at smc.vnet.net...
> Suppose you have a list of lists, something like
> {{1, 6, 7}, {3, 6, 9}, {1, 2, 11}, {3, 5, 9}, {2, 5, 6}, {2, 9, 11}, {
>   2, 10, 11}, {3, 7, 9}, {5, 8, 11}, {3, 7, 9}, {7, 8, 9}, {2, 5, 12},
> {2, 6,
>     10}, {2, 10, 11}, {1, 6, 9}, {6, 10, 12}, {3, 6, 12}, {2, 5, 12},
> {3, 8,
>      9}, {1, 2, 7}}
> and you want to delete cases matching several different patterns, say
> {1,_,_} and {9,_,_}
> What's the most efficient way?

Use a pattern with Alternatives (|):

DeleteCases[list, {1 | 9, _, _}]

> Also, can you use conditions with DeleteCases?  Say, I want to delete
> all cases containing even numbers?

You can use a conditional rule (/;) to achieve this:

DeleteCases[list, x_ /; Or @@ EvenQ[x]]

Best regards,

  Eckhard

-- 
Dr.-Ing. Eckhard Hennig
www.kaninkolo.de/ai
aidev \at kaninkolo \dot de



  • Prev by Date: AW: Using a Result from NMinimize
  • Next by Date: Re: Re: Tr vs Total
  • Previous by thread: Re: DeleteCases : several at once, conditions
  • Next by thread: RE: DeleteCases : several at once, conditions