[R] Odp: Filtering R lists

[Petr PIKAL]

Hi


r-help-bounces at r-project.org napsal dne 04.03.2009 13:18:30:

> Hello
> I am am new to R and any help with the following would be appreciated:
> I have a list (example attached) and I would like to create a new list 
> which is a filtered version of this list. I.e I would like a list that 
> only contains elements with this value:
> 
> Chr 10 : 21853562 - 21855482

Lists can have quite complicated structure so here is only a small 
suggestion

lapply(your.list, function(x) x==desired.value)

This shall give you list of logical values if your list has only one 
level. 

Something like

pts <- list(x=mtcars[,1], y=mtcars[,2], z=mtcars[,10])
pts[which(unlist(lapply(pts, function(x) sum(x==4)>0)))]

Regards
Petr

> 
> Any pointers/tips would be great.
> Thanks!
> Nikol
> 
> -- 
> Bioinformatician/Computer Associate
> Cambridge Institute for Medical Research
> University of Cambridge
> Wellcome Trust/MRC Building
> Hills Road
> Cambridge
> CB2 0XY
> 01223 762111 
> 
> [[1]]
> human../US45102804_251757910002_S01_CGH-v4_95_Feb07.chr10.cher1
> Chr 10 : 21853562 - 21855482
> Antibody : ./US45102804_251757910002_S01_CGH-v4_95_Feb07
> Maximum level = 0.5370385
> Score = 3.193875
> Spans 19 probes.
> Defined extras: typeUpstream, typeInside, distMid2TSS, upSymbol, 
inSymbol, type
> 
> [[2649]]
> human../US45102804_252058310010_S01_CGH-v4_95_Feb07.chrX.cher18
> Chr X : 72387424 - 72387712
> Antibody : ./US45102804_252058310010_S01_CGH-v4_95_Feb07
> Maximum level = 0.3504706
> Score = 0.4045575
> Spans 4 probes.
> Defined extras: typeUpstream, typeInside, distMid2TSS, upSymbol, 
inSymbol, type
> 
> [[2650]]
> human../US45102804_252058310010_S01_CGH-v4_95_Feb07.chrX.cher19
> Chr X : 129037305 - 129037494
> Antibody : ./US45102804_252058310010_S01_CGH-v4_95_Feb07
> Maximum level = 0.4718157
> Score = 0.5751177
> Spans 3 probes.
> Defined extras: typeUpstream, typeInside, distMid2TSS, upSymbol, 
inSymbol, type
> 
> [[2651]]
> human../US45102804_252058310010_S01_CGH-v4_95_Feb07.chrX.cher20
> Chr X : 129048386 - 129048865
> Antibody : ./US45102804_252058310010_S01_CGH-v4_95_Feb07
> Maximum level = 0.3711013
> Score = 0.4121159
> Spans 5 probes.
> Defined extras: typeUpstream, typeInside, distMid2TSS, upSymbol, 
inSymbol, type
> 
> [[2652]]
> human../US45102804_252058310010_S01_CGH-v4_95_Feb07.chrX.cher21
> Chr X : 129065300 - 129066038
> Antibody : ./US45102804_252058310010_S01_CGH-v4_95_Feb07
> Maximum level = 0.4387153
> Score = 1.515073
> Spans 8 probes.
> Defined extras: typeUpstream, typeInside, distMid2TSS, upSymbol, 
inSymbol, type
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