Scenario 1

I have a datamatrix of RNAseq data, the ID column looks something like the following

-----------------
head(geneIDs)
-----------------
"Xkr4|497097|locus1of1|1"  
"Sox17|20671|locus1of1|5"  
"Mrpl15|27395|locus1of1|3"
"Lypla1|18777|locus1of1|1" 
"Tcea1|21399|locus1of1|3"  
"Rgs20|58175|locus1of1|3" 

I want to parse them out and retain only the gene symbols, “sapply” here is very handy

as.vector(sapply (geneIDs, FUN = function (x) {strsplit(x, "\\|")[[1]][1]}))

Running the above line get me the following:

"Xkr4"  
"Sox17"  
"Mrpl15"
"Lypla1" 
"Tcea1"  
"Rgs20"