Read all worksheets in an Excel workbook into an R list with data.frames

Updated answer using readxl (22nd June 2015)

Since posting this question the readxl package has been released. It supports both xls and xlsx format. Importantly, in contrast to other excel import packages, it works on Windows, Mac, and Linux without requiring installation of additional software.

So a function for importing all sheets in an Excel workbook would be:

library(readxl)    
read_excel_allsheets <- function(filename, tibble = FALSE) {
    # I prefer straight data.frames
    # but if you like tidyverse tibbles (the default with read_excel)
    # then just pass tibble = TRUE
    sheets <- readxl::excel_sheets(filename)
    x <- lapply(sheets, function(X) readxl::read_excel(filename, sheet = X))
    if(!tibble) x <- lapply(x, as.data.frame)
    names(x) <- sheets
    x
}

This could be called with:

mysheets <- read_excel_allsheets("foo.xls")

Old Answer

Building on the answer provided by @mnel, here is a simple function that takes an Excel file as an argument and returns each sheet as a data.frame in a named list.

library(XLConnect)

importWorksheets <- function(filename) {
    # filename: name of Excel file
    workbook <- loadWorkbook(filename)
    sheet_names <- getSheets(workbook)
    names(sheet_names) <- sheet_names
    sheet_list <- lapply(sheet_names, function(.sheet){
        readWorksheet(object=workbook, .sheet)})
}

Thus, it could be called with:

importWorksheets('test.xls')