r - R3.4.1 Read data from multiple .csv files -

i'm trying build function can import/read several data tables in .csv files, , compute statistics on selected files. each of 332 .csv file contains table same column names: date, pollutant , id. there lot of missing values.

this function wrote far, compute mean of values pollutant:

pollutantmean <- function(directory, pollutant, id = 1:332) {     library(dplyr)   setwd(directory)   good<-c()    (i in (id)){     task1<-read.csv(sprintf("%03d.csv",i))   }    p<-select(task1, pollutant)   good<-c(good,complete.cases(p))   mean(p[good,])  } 

the problem have each time goes through loop new file read , data read replaced data new file. end function working fine 1 single file, not when want select multiple files e.g. if ask id=10:20, end mean calculated on file 20.

how change code can select multiple files?

thank you!

my answer offers way of doing want (if understood correctly) without using loop. 2 assumptions are: (1) have 332 *.csv files same header (column names) - file of same structure, , (2) can combine tables 1 big data frame.

if these 2 assumptions correct, use list of files import files data frames (so answer not contain loop function!).

# creates list name of file. have provide path folder. file_list <- list.files(path = [your path *.csv files saved in], full.names = true)  # create list of data frames. mylist <- lapply(file_list, read.csv)  # 'row-bind' data frames of list 1 big list. mydata <- rbindlist(mylist)  # can perform calculation on big data frame, using column information filter or subset information of subset of table (if necessary). 

i hope helps.