I have a piece of code, I want to cbind my data. The catch is I will not always have eighta data files to cbind. I would like to keep the code below and import just five, if I have five. The reason is this. I will will always have between 1 - 100 dataframes to cbind, I dont want always manually tell R to cbind one or 100. I want to just have cbind (1 :100) and always cbind what needs to be cbind.
finaltable<- cbind(onea, twoa, threea, foura, fivea, sixa, sevena, eighta)
Without more data, here's a contrived example. First, I'll make some example files with the same number of rows in each:
filenames <- paste0(c('onea', 'twoa', 'threea', 'foura'), '.csv')
for (fn in filenames)
write.csv(matrix(runif(5), nc = 1), file = fn, row.names = FALSE)
Let's first dynamically derive a list of filenames to process. (This code is assuming that the previous lines making these files did not happen.)
(filenames <- list.files(pattern = '*.csv'))
## [1] "foura.csv" "onea.csv" "threea.csv" "twoa.csv"
This is the "hard" part, reading the files:
(ret <- do.call(cbind, lapply(filenames,
function(fn) read.csv(fn, header = TRUE))))
## V1 V1 V1 V1
## 1 0.9091705 0.4934781 0.7607488 0.4267438
## 2 0.9692987 0.4349523 0.6066990 0.9134305
## 3 0.6444404 0.8639983 0.1473830 0.9844336
## 4 0.7719652 0.1492200 0.7731319 0.9689941
## 5 0.9237107 0.6317367 0.2565866 0.1084299
For proof of concept, here's the same thing but operating on a subset of the vector of filenames, showing that the length of the vector is not a concern:
(ret <- do.call(cbind, lapply(filenames[1:2],
function(fn) read.csv(fn, header = TRUE))))
## V1 V1
## 1 0.9091705 0.4934781
## 2 0.9692987 0.4349523
## 3 0.6444404 0.8639983
## 4 0.7719652 0.1492200
## 5 0.9237107 0.6317367
You may want/need to redefine the names of the columns (with names(ret) <- filenames, for example), but you can always reference the columns by numbered indexing (e.g., ret[,2]) without worrying about names.