Sometimes the following function call causes a database exception:

>  gene.seq <- getSequence (id=gene.map[,"ensembl_transcript_id"], type="ensembl_transcript_id",
+                              seqType="3utr", mart=hmart)

I understand the above function must be called by try to capture the eventual error.
WHat is not clear to me is how to realize that an error has occurred. The on-line documentation 
mentions an invisible object of class "try-error".
How shall I test whetehr such object has been created or not ?
I assume it is created whenever an error does occur ....?

Thank you for your help.
Maura 


tutti i telefonini TIM!


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