read.table               package:base               R Documentation

_D_a_t_a _I_n_p_u_t

_D_e_s_c_r_i_p_t_i_o_n:

     Reads a file in table format and creates a data frame from it,
     with cases corresponding to lines and variables to fields in the
     file.

_U_s_a_g_e:

     read.table(file, header = FALSE, sep = "", quote = "\"'", dec = ".",
                row.names, col.names, as.is = FALSE, na.strings = "NA",
                skip = 0, check.names = TRUE, fill = FALSE,
                strip.white = FALSE, blank.lines.skip = TRUE)

     read.csv(file, header = TRUE, sep = ",", quote="\"", dec=".",
              fill = TRUE, ...)

     read.csv2(file, header = TRUE, sep = ";", quote="\"", dec=",",
              fill = TRUE, ...)

     read.delim(file, header = TRUE, sep = "\t", quote="\"", dec=".",
              fill = TRUE, ...)

     read.delim2(file, header = TRUE, sep = "\t", quote="\"", dec=",",
              fill = TRUE, ...)

_A_r_g_u_m_e_n_t_s:

    file: the name of the file which the data are to be read from. Each
          row of the table appears as one line of the file.  If it does
          not contain an absolute path, the file name is relative to
          the current working directory, `getwd()'.

          Alternatively, `file' can be a `connection', which will be
          opened if necessary, and if so closed at the end of the
          function call.  However, since the file must be read twice,
          this will be resource-intensive except on seekable
          connections. 

  header: a logical value indicating whether the file contains the
          names of the variables as its first line.  If missing, the
          value is determined from the file format: `header' is set to
          `TRUE' if and only if the first row contains one fewer field
          than the second.

     sep: the field separator character.  Values on each line of the
          file are separated by this character.  If `sep = ""' the
          separator is ``white space'', that is one or more spaces,
          tabs or newlines.

   quote: the set of quoting characters. To disable quoting altogether,
          use `quote=""'.  See `scan' for the behaviour on quotes
          embedded in quotes.

     dec: the character used in the file for decimal points.

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: the default behavior of `read.table' is to convert
          non-numeric variables to factors.  The variable `as.is'
          controls this conversion.  Its value is either a vector of
          logicals (values are recycled if necessary), or a vector of
          numeric indices which specify which columns should be left as
          character strings.

na.strings: a vector strings which are to be interpreted as `NA'
          values.

    skip: the number of lines of the data file to skip before beginning
          to read data.

check.names: logical.  If `TRUE' then the names of the variables in the
          data frame are checked to ensure that they are syntactically
          valid variable names.  If necessary they are adjusted (by
          `make.names') so that they are.

    fill: logical. If `TRUE' then in case the rows have unequal length,
          blank fields are implicitly added.

strip.white: logical. Used only when `sep' has been specified, and
          allows the stripping of leading and trailing white space from
          `character' fields (`numeric' fields are always stripped). 
          See `scan' for further details, remembering that the columns
          may include the row names.

blank.lines.skip: logical: if `TRUE' blank lines in the input are
          ignored.

     ...: Further arguments to `read.table'.

_D_e_t_a_i_l_s:

     If `row.names' is not specified and the header line has one less
     entry than the number of columns, the first column is taken to be
     the row names.  This allows data frames to be read in from the
     format in which they are printed.

     `read.csv' and `read.csv2' are identical to `read.table' except
     for the defaults.  They are intended for reading ``comma separated
     value'' files (`.csv') or the variant used in countries that use a
     comma as decimal point and a semicolon as field separator. 
     Similarly, `read.delim' and `read.delim2' are for reading
     delimited files, defaulting to the TAB character for the
     delimiter.  Notice that `header = TRUE' and `fill = TRUE' in these
     variants.

_V_a_l_u_e:

     A data frame (`data.frame') containing a representation of the
     data in the file.

     This function is the principal means of reading tabular data into
     R.

_N_o_t_e:

     The implementation of `read.table' currently reads everything as
     character using `scan' and subsequently defines `"numeric"' or
     `factor' variables.

     This is quite memory consuming for files of thousands of records
     and may need larger memory, see `Memory'.

_S_e_e _A_l_s_o:

     The `R Data Import/Export' manual.

     `scan', `read.fwf' for reading fixed width formatted input;
     `read.table.url' for ``reading'' data from the internet;
     `write.table'; `data.frame'.

