Last chance! 50% off unlimited learning
Sale ends in
Read a contiguous set of columns from sheet into an R data.frame.
Uses the RInterface for speed.
readColumns(sheet, startColumn, endColumn, startRow,
endRow=NULL, as.data.frame=TRUE, header=TRUE, colClasses=NA,
...)a Worksheet object.
a numeric value for the starting column.
a numeric value for the ending column.
a numeric value for the starting row.
a numeric value for the ending row. If NULL it
reads all the rows in the sheet. If you request more than the
existing rows in the sheet, the result will be truncated by the
actual row number.
a logical value indicating if the result should
be coerced into a data.frame. If FALSE, the result is
a list with one element for each column.
a logical value indicating whether the first row
corresponding to the first element of the rowIndex vector
contains the names of the variables.
a character vector that represents the class of each
column. Recycled as necessary, or if NA an attempt is made
to guess the type of each column by reading the first row of data.
Only numeric, character, Date, POSIXct,
column types are accepted. Anything else will be coverted to a
character type. If the length is less than the number of
columns requested, replicate it.
other arguments to data.frame, for example
stringsAsFactors
A data.frame or a list, depending on the as.data.frame
argument.
Use the readColumns function when you want to read a rectangular
block of data from an Excel worksheet. If you request columns which
are blank, these will be read in as empty character "" columns.
Internally, the loop over columns is done in R, the loop over rows is
done in Java, so this function achieves good performance when number of
rows >> number of columns.
Excel internally stores dates and datetimes as numeric values, and does
not keep track of time zones and DST. When a numeric column is
formatted as a datetime, it will be converted into POSIXct class
with a GMT timezone. If you need a Date column, you need
to specify explicitly using colClasses argument.
For a numeric column Excels's errors and blank cells will be returned as
NaN values. Excel's #N/A will be returned as NA. Formulas will be
evaluated. For a chracter column, blank cells will be returned as "".
read.xlsx2 for reading entire sheets.
See also addDataFrame for writing a data.frame to a
sheet.
# NOT RUN {
file <- system.file("tests", "test_import.xlsx", package = "xlsx")
wb <- loadWorkbook(file)
sheets <- getSheets(wb)
sheet <- sheets[["all"]]
res <- readColumns(sheet, startColumn=3, endColumn=10, startRow=3,
endRow=7)
sheet <- sheets[["NAs"]]
res <- readColumns(sheet, 1, 6, 1, colClasses=c("Date", "character",
"integer", rep("numeric", 2), "POSIXct"))
# }
Run the code above in your browser using DataLab