CODEWITHSUNDEEP
r
changjx
changjx

Reputation: 397

R read files name and put it into variable

i have a series of data, it looks like 

sale20160101.txt, 

sales20160102.txt,...,

sales20171231.

now i want to read them all and combine, but it also needs a date variable to help me identify their occurrence time,so the date variable will be 20160101,20160102,...,20161231.

my ideas is:

split filename into sale+"time"

duplicate time whenever i read according to number of data length

cbind data and time.

thx alot.

Upvotes: 1

Views: 981

Answers (2)

akrun
akrun

Reputation: 887951

We could do this with fread and rbindlist from data.table

library(data.table)
#find the files that have names starting as 'sales' followed by numbers
#and have .txt extension
files <- list.files(pattern = "^sale.*\\d+\\.txt", full.names = TRUE)

#get the dates
dates <-   readr::parse_number(basename(files))

#read the files into a list and rbind it 
dt <- rbindlist(setNames(lapply(files, fread), dates), idcol = 'date')

Upvotes: 1

Axeman
Axeman

Reputation: 35392

I usually would do a variation of the following:

# find the files
ls <- list.files(pattern = '^sales')
# Get the dates
dates <- gsub('sales', '', tools::file_path_sans_ext(ls))

# read in the data
dfs <- lapply(ls, read.table)
# match the dates
names(dfs) <- dates

# bind all data together and include the date as a column
df <- dplyr::bind_rows(dfs, .id = 'date')

Upvotes: 1

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