

scan {base}                                  R Documentation

_R_e_a_d _D_a_t_a _V_a_l_u_e_s

_D_e_s_c_r_i_p_t_i_o_n_:

     Read data into a vector or list from the console or
     file.

_U_s_a_g_e_:

     scan(file = "", what = double(0), nmax = -1, n = -1, sep = "",
          skip = 0, nlines = 0, na.strings = "NA", flush = FALSE,
          strip.white = FALSE, quiet = FALSE)

_A_r_g_u_m_e_n_t_s_:

    file: the name of a file to read data values from.  If
          the specified file is `""', then input is taken
          from the keyboard (in this case input can be ter-
          minated by a blank line).

          Otherwise, the file name is relative to the cur-
          rent working directory, `getwd()', unless it spec-
          ifies an absolute path.

    what: the type of `what' gives the type of data to be
          read.  If `what' is a list, it is assumed that the
          lines of the data file are records each containing
          `length(what)' items (``fields'').

    nmax: the maximum number of data values to be read, or
          if `what' is a list, the maximum number of records
          to be read.  If omitted, `scan' will read to the
          end of `file'.

       n: the maximum number of data values to be read,
          defaulting to no limit.

     sep: by default, scan expects to read white-space
          delimited input fields.  Alternatively, `sep' can
          be used to specify a character which delimits
          fields.

    skip: this many lines of the input file should be
          skipped before starting to read data values.

  nlines: the maximum number of lines of data to be read.

na.strings: character string, indicating which character
          fields in the file should translate to missing
          (`NA') values.

   flush: logical; if `TRUE', `scan' will flush to the end
          of the line after reading the last of the fields
          requested.  This allows putting comments after the
          last field.

strip.white: vector of logical value(s) corresponding to
          items in the `what' argument. It is used only when
          `sep' has been specified, and allows to strip
          leading and trailing white space from `character'
          fields (`numeric' fields are always stripped).

          If `strip.white' is of length 1, it applies to all
          fields; otherwise, if `strip.white[i]' is `TRUE'
          and the `i'-th field is character (because
          `what[i]' is), then the leading and trailing white
          space from field `i' is stripped.

   quiet: logical; if `FALSE' (default), scan(.) will print
          a line, telling what fields have been read.

_D_e_t_a_i_l_s_:

     The value of `what' can be a list of types, in which
     case `scan' returns a list of vectors with the types
     given by the types of the elements in `what'.  This
     provides a way of reading columnar data.

     Keyboard entry is terminated by typing a blank line.

_S_e_e _A_l_s_o_:

     `read.table' for more user-friendly reading of data
     matrices; `write'.

_E_x_a_m_p_l_e_s_:

     cat("TITLE extra line", "2 3 5 7", "11 13 17", file="ex.data", sep="\n")
     pp <- scan("ex.data", skip = 1, quiet= TRUE)
         scan("ex.data", skip = 1)
         scan("ex.data", skip = 1, nlines=1)# only 1 line after the skipped one
     str(scan("ex.data", what = list("","",""))) # flush is F -> read "7"
     str(scan("ex.data", what = list("","",""), flush = TRUE))

