问题:

R 3.0.3: I have 40 csv files all structured the same that I want to rbind into one file so I can calculate the mean of one column.

I searched:

I cannot find the answer.

Any suggestions/pointers?

回答1:

Using the answer from here [Importing several files and indexing them ]

list files with .csv extension - this assumes that the only .csv files in your working directory are the ones you want to read

files  <- list.files(pattern = '\\.csv')

read files into a list - are there headers?

tables <- lapply(files, read.csv, header = TRUE)

rbind files

combined.df <- do.call(rbind , tables)

You can then find the mean - find which columns are numeric

s <- sapply(combined.df, is.numeric)

find the mean of numeric variables

colMeans(combined.df[s])

In more contemporary plyr approach:

files <- list.files(...)
data <- adply(files, 1, read.table)

(it's saturday afternoon: untested code, but the approach is fine)