R : read.table : Read data from file

“read.table” method is used to read data from a file in table format.

read.table(file, header = FALSE, sep = "", quote = "\"'",

           dec = ".", numerals = c("allow.loss", "warn.loss", "no.loss"),

           row.names, col.names, as.is = !stringsAsFactors,

           na.strings = "NA", colClasses = NA, nrows = -1,

           skip = 0, check.names = TRUE, fill = !blank.lines.skip,

           strip.white = FALSE, blank.lines.skip = TRUE,

           comment.char = "#",

           allowEscapes = FALSE, flush = FALSE,

           stringsAsFactors = default.stringsAsFactors(),

           fileEncoding = "", encoding = "unknown", text, skipNul = FALSE)

Parameter	Description
file	The name of the file to read data from. Each line of the file corresponds to a row in table.
header	Header indicates whether the file contains names of the variables as firstline.
sep	Field separator character, It can be white space, tab, comma (,) etc.,
quote	The set of quoting characters. To disable quoting, use quote = ""
dec	The character used in the file for decimal points.
numerals	Indicate how to convert numbers
row.names	A vector of row names. This can be a vector giving the actual row names, or a single number giving the column of the table which contains the row names, or character string giving the name of the table column containing the row names.
col.names	A vector of optional names for the variables. The default is to use "V" followed by the column number.
as.is	By defult, read.table converts character variables to factors. You can control this behavior by using as.is.
na.strings	A character vector of strings which are to be interpreted as NA values. Blank fields are also considered to be missing values in logical, integer, numeric and complex fields.
colClasses	A vector of classes to be assumed for the columns.
nrows	Maximum number of rows to read.
skip	Skip number of lines before reading data.
check.names	If it is set to TRUE, then the names of the variables in the data frame are checked to ensure that they are syntactically valid variable names.
fill	If it is set to TRUE, blank fields are added, if rown are unequal length.
strip.white	used for the stripping of leading and trailing white space from unquoted character fields
blank.lines.skip	If it is set to TRUE, then blank lines in the input are ignored.
comment.char	It is a character vector of length 1, used to specify comment symbol.

Let’s say employee.txt contains following data.

"firstName" "lastName"

"Hari Krishna" "Gurram"

"Joel" "Chelli"

"Rama Krishna" "Gurram"

"Sudheer" "Ganji"

> table2 <- read.table("employee.txt")
> 
> table2
            V1       V2
1    firstName lastName
2 Hari Krishna   Gurram
3         Joel   Chelli
4 Rama Krishna   Gurram
5      Sudheer    Ganji
> 
> table2 <- read.table("employee.txt", skip=2)
> 
> table2
            V1     V2
1         Joel Chelli
2 Rama Krishna Gurram
3      Sudheer  Ganji

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