[BioC] GRanges list and reduce function

Asma rabe asma.rabe at gmail.com
Fri Aug 15 12:20:30 CEST 2014


Hi ,


I need a Granges object with exons data for  few chromosomes, i got Granges
list of transcripts and their exons as follows:


library("TxDb.Hsapiens.UCSC.hg19.knownGene")

txdb<-TxDb.Hsapiens.UCSC.hg19.knownGene

tx_Exons<-exonsBy(txdb)



1-How to use reduce on Granges list?how to get the unique exons only and
exclude redundant exons?


2-How to select exons of certain chromosomes only ex: chr10? i tried the
following but i wonder why i got  GRnages list with empty Grange lists??


chr10<-tx_Exons[seqnames(tx_Exons)=="chr10",]


>chr10

GRangesList of length 80922:

$1

GRanges with 0 ranges and 3 metadata columns:

   seqnames    ranges strand |   exon_id   exon_name exon_rank

      <Rle> <IRanges>  <Rle> | <integer> <character> <integer>


$2

GRanges with 0 ranges and 3 metadata columns:

     seqnames ranges strand | exon_id exon_name exon_rank


$3

GRanges with 0 ranges and 3 metadata columns:

     seqnames ranges strand | exon_id exon_name exon_rank


...

<80919 more elements>

---

seqlengths:

                  chr1                  chr2 ...        chrUn_gl000249

             249250621             243199373 ...                 38502



> length(chr10)

[1] 80922

> length(tx_Exons)

[1] 80922


Thank you

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