merge - Change column names after merging multiple data frames into one in R -
after merging multiple data frames one, know how change column headers in master data frame represent original files came from. merged large number of data frames 1 using code below:
library(plyr) dflist = list.files(path=dir, pattern="csv$", full.names=true, recursive=false) import.list = llply(dflist, read.csv) master = reduce(function(x, y) merge(x, y, by="hours"), import.list)
i columns belonged each original data frame named unique id original data frame/ csv file named (i.e. aa, ab, ac). unique ids in filenames comes before low line ("_") can isolate them using code below. however, having trouble applying column headers. appreciated.
filename = dflist[1] unqid = strsplit(filename,"_")[[1]][1]
you define function in llply
call , have read.csv
assign names. or rename them after reading them in , before merging @joran suggested
#first names filenames = dflist #i unsure line below, unqid = lapply(filenames,function(x) strplit(x,"_")[1]) names(import.list) <- paste("unqid", names(import.list),sep=".") #renaming list items
and merge using code
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