r - What is the most efficient way to change the case of column names in a data.table? -


sometimes before merging it's useful change case of column names consistency. when working data.frame pretty straightforward (as outlined here); although same solution works on ``data.table`, throws warning. example, 

ran <- rep(34,50) dom <- rep("cat",50) table <- rep("pig", 50)  dt <- data.table(ran,dom,table); head(dt)    ran dom table 1:  34 cat   pig 2:  34 cat   pig 3:  34 cat   pig 4:  34 cat   pig 5:  34 cat   pig 6:  34 cat   pig  ##the data.frame way  names(dt) <- toupper(names(dt))  ##the error  warning message: in `names<-.data.table`(`*tmp*`, value = c("ran", "dom", "table" :   names(x)<-value syntax copies whole table. due <- in r   itself. please change setnames(x,old,new) not copy , faster.   see help('setnames'). can safely ignore warning if inconvenient   change right now. setting options(warn=2) turns warning error,   can use traceback() find , change names<- calls.

i've used following workaround avoid error, , it's faster on wide datasets, there data.table way this? 

##the work around upper <- toupper(names(dt))  setnames(dt,upper);head(dt)     ran dom table 1:  34 cat   pig 2:  34 cat   pig 3:  34 cat   pig 4:  34 cat   pig 5:  34 cat   pig 6:  34 cat   pig

to give answer, comments say, setnames data.table function , data.table recommended way (as long warning data.table suggests); e.g.,

setnames(dt,toupper(names(dt)))

not confused setnames function stats package! (note upper case n).


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