rename the multiple columns in R - r

Question

I have 1000 files with column similar column names.for example :
df1
DATE PRICE CLOSE
df2
DATE PRICE CLOSE
and so on...
If I try to merge them based by date they do get merge but the columns have retained their old names and I want to rename them in a loop
so merge data set looks like this
Date Price Close PRICE CLOSE
I want something like
DATE PRICE1 CLOSE1 PRICE2 CLOSE2.
Is there any easy way to do it?
I have tried couple of things which is not giving me correct output
this is using plyr package:
mod_join = function(mypath){
filenames=list.files(path=mypath, full.names=TRUE)
datalist = lapply(filenames, function(x){read.csv(file=x,header=T)[,c('Date','High','Low')]})
join_all(datalist,by = "Date")
}
this is using merge command on all data frame:
merge2 = function(mypath){
filenames=list.files(path=mypath, full.names=TRUE)
datalist = lapply(filenames, function(x){read.csv(file=x,header=T)[,c('Date','High','Low')]})
Reduce(function(x,y) {merge(x,y,by.x= "Date",by.y = "Date",all=T)}, datalist)}
}
I tried using for loop by making the data frame lead then using each data frame to subset and merge subsequently but somehow its not subsetting the dataframes:
for (i in 1:1000){
data_subset <- sprintf('data_%d',i)
mydata_subset <- data.frame(,data_subset["Date"],data_subset["High"],data_subset["DayLow"])
obj_name <- paste('subset_Pricedata',i,sep ="_")
assign(obj_name,value = mydata_subset)
}
Any help will be great.
Thanks

Answer 1

Hopefully, this will do your job:
library(plyr)
df1 = rename(df1,c("PRICE"="PRICE1","CLOSE"="CLOSE1"))
df2 = rename(df2,c("PRICE"="PRICE2","CLOSE"="CLOSE2"))
new = merge(df1,df2,all=TRUE)
Please comment if you face any difficulties.

Answer 2

What about this approach?
It should be fast as it uses data.table and its fread-function
library(data.table)
merge2 <- function(mypath){
filenames <- list.files(path=mypath, full.names=TRUE)
fileslist <- lapply(filenames, function(nam){
# reads the file
file <- fread(nam)
setnames(file, 2, "price") # renames the second col to "price"
setnames(file, 3, "close") # third to "close"
return(file)
})
dat <- rbindlist(fileslist)
return(dat)
}
EDIT
I just realised that you want to merge your data instead of having it in the long format. What you can do is just add a variable with a name to the data.table "file" before returning the file by adding:
file[, varnam := nam]
and then cast the final data.table "dat" before returning it, using the reshape2 library and its dcast function.

Answer 3

I had a similar problem. Here's what I ended up using, although there is likely a cleaner way.
The function suffix_col_names will add a suffix to a subset of columns. I use this because I eventually merge week1 and week 2 data on columns 1-10.
#function called suffix_col_names
suffix_col_names<-function(your_df, start_col, end_col, your_str, your_sep){
for (i in start_col:end_col){
colnames(your_df)[i]<-paste(colnames(your_df)[i], sep=your_sep,your_str)
}
return(your_df)
}
#call function to rename columns in week1 and week2
week_1_data<-suffix_col_names(week1,11,24,"1",".")
week_2_data<-suffix_col_names(week2,11,24,"2",".")