[R] List filtration

[Dimitris Rizopoulos]

try this:

lis. <- lapply(lis, function(x) if (length(ind <- grep("^IPI", x))) 
x[ind[1]] else NULL)
lis.[!sapply(lis., is.null)]


I hope it helps.

Best,
Dimitris

----
Dimitris Rizopoulos
Ph.D. Student
Biostatistical Centre
School of Public Health
Catholic University of Leuven

Address: Kapucijnenvoer 35, Leuven, Belgium
Tel: +32/(0)16/336899
Fax: +32/(0)16/337015
Web: http://med.kuleuven.be/biostat/
     http://www.student.kuleuven.be/~m0390867/dimitris.htm


----- Original Message ----- 
From: "Johannes Graumann" <johannes_graumann at web.de>
To: <r-help at stat.math.ethz.ch>
Sent: Thursday, February 22, 2007 3:33 PM
Subject: [R] List filtration


> Hello R-ologists,
>
> Imagine you have a list "list" like so:
>
>>list
> [[1]]
> [1] "IPI00776145.1" "IPI00776187.1"
>
> [[2]]
> [1] "Something" "IPI00807764.1" "IPI00807887.1"
>
> [[3]]
> [1] "IPI00807764.1"
>
> [[4]]
> [1] "Somethingelse"
>
> What I need to achieve is a filtered list "list2" like so:
>
>>list2
> [[1]]
> [1] "IPI00776145.1"
>
> [[2]]
> [1] "IPI00807764.1"
>
> [[3]]
> [1] "IPI00807764.1"
>
> So:
> - if sublist-entry 1 start with "^IPI" make it the list-entry.
> - otherwise chose the first "^IPI" sublist-entry present.
> - delete the list-entry if not "^IPI" sublist-entry present.
>
> Can anybody nudge me towards an elegant solution without looping - I 
> have
> LOTS of entries to process ...
>
> Thanks for your Teachings,
>
> Joh
>
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide 
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
> 


Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm