replace numbers inside an XML element using xmlValue

I have bunch of numbers

preKId_2015 = c(242938L, 339402L, 361888L, 428033L, 442546L, 309790L, 355662L, 
458179L, 465105L, 490383L, 524644L, 526614L, 539453L, 555516L, 
569709L)

I have an xml file with some other id values already between the elements

<input-id> 
"PreKId"
12344 
33433
23343
93893
23333
</input-id>

I am trying to replace these pre-existing values with the values form preKId_2015. I tried

 doc <- xmlParseDoc("C:/... ProjectKids/test12.xml")
 nodes <- getNodeSet(doc, "//input-id")[[1]]
 xmlValue(nodes) =  replace(xmlValue(nodes),xmlValue(nodes),preKId_2015)

I get a warning and nothing happens

 Warning message:
 In replace(xmlValue(nodes), xmlValue(nodes),preKId_2015) :
   number of items to replace is not a multiple of replacement length

Need help