type.convert              package:utils              R Documentation

Type Conversion on Character Variables

Description:

     Convert a character vector to logical, integer, numeric, complex
     or factor as appropriate.

Usage:

     type.convert(x, na.strings = "NA", as.is = FALSE, dec = ".")

Arguments:

       x: a character vector.

na.strings: a vector of strings which are to be interpreted as 'NA'
          values.  Blank fields are also considered to be missing
          values in logical, integer, numeric or complex vectors.

   as.is: logical.  See 'Details'.

     dec: the character to be assumed for decimal points.

Details:

     This is principally a helper function for 'read.table'. Given a
     character vector, it attempts to convert it to logical, integer,
     numeric or complex, and failing that converts it to factor unless
     'as.is = TRUE'.  The first type that can accept all the
     non-missing values is chosen.

     Vectors which are entirely missing values are converted to
     logical, since 'NA' is primarily logical.

     Since this is a helper function, the caller should always pass an
     appropriate value of 'as.is'.

Value:

     A vector of the selected class, or a factor.

See Also:

     'read.table'

