id2name: Map internal ids to external names for a given feature type
In jmacdon/GenomicFeatures: Conveniently import and query gene models

Description Usage Arguments Details Value Author(s) See Also Examples

Utility function for retrieving the mapping from the internal ids to the external names of a given feature type.

1	id2name(txdb, feature.type=c("tx", "exon", "cds"))

`txdb`	A TxDb object.
`feature.type`	The feature type for which the mapping must be retrieved.

Transcripts, exons and CDS in a TxDb object are stored in seperate tables where the primary key is an integer called feature internal id. This id is stored in the "tx_id" column for transcripts, in the "exon_id" column for exons, and in the "cds_id" column for CDS. Unlike other commonly used ids like Entrez Gene IDs or Ensembl IDs, this internal id was generated at the time the TxDb object was created and has no meaning outside the scope of this object.

The id2name function can be used to translate this internal id into a more informative id or name called feature external name. This name is stored in the "tx_name" column for transcripts, in the "exon_name" column for exons, and in the "cds_name" column for CDS.

Note that, unlike the feature internal id, the feature external name is not guaranteed to be unique or even defined (the column can contain NAs).

A named character vector where the names are the internal ids and the values the external names.

Hervé Pagès

transcripts, transcriptsBy, and transcriptsByOverlaps, for how to extract genomic features from a TxDb object.
The TxDb class.

txdb1_file <- system.file("extdata", "hg19_knownGene_sample.sqlite",
                          package="GenomicFeatures")
txdb1 <- loadDb(txdb1_file)
id2name(txdb1, feature.type="tx")[1:4]
id2name(txdb1, feature.type="exon")[1:4]
id2name(txdb1, feature.type="cds")[1:4]

txdb2_file <- system.file("extdata", "Biomart_Ensembl_sample.sqlite",
                          package="GenomicFeatures")
txdb2 <- loadDb(txdb2_file)
id2name(txdb2, feature.type="tx")[1:4]
id2name(txdb2, feature.type="exon")[1:4]
id2name(txdb2, feature.type="cds")[1:4]