Project page: https://r-forge.r-project.org/projects/readcsvcolumns/
http://r-forge.r-project.org/for source package and MS-Windows binaries
http://research.edm.uhasselt.be/jori/for OS X binaries
This package provides a single function called
read.csv.columns. Like other
functions, this allows you to read data from a CSV file, but here you need to
specify in advance what type each column is.
The signature of the function is
read.csv.columns(file.name, column.types="", max.line.length=16384, has.header=TRUE, num.threads=1)
where the meaning of the arguments is as follows:
file.name: the path to the CSV file
column.types: a string containing as many characters as there are columns in the
CSV file. If this string is empty, the data type of each column will be guessed based
on the first line containing data. The allowed characters in this string and their
i: the column contains integers
r: the column contains real numbers
s: the column contains arbitrary strings
.: the column should be ignored
max.line.length: specifies an upper limit to the length of a line in the CSV file (the
default is probably more than enough)
has.header: if set to
TRUE (the default), the values of the first line are used as
labels for the columns of the CSV file. If set to
FALSE, the first line is also
considered to consist of data values.
num.threads: By default, a single processor thread is used to parse the strings into numbers.
If this is set to a number larger than one, this amount of threads will
be used to parse this data, possibly offering a speedup. If the number
is zero or negative, the amount of cores as reported by
function (from the
parallel package) will be used.
The function returns a list where each entry corresponds to a column in the CSV file. The columns that were marked as 'ignored', are not present in this list.