R: Type Conversion on Character Variables

type.convert {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.

Vectors containing `F`, `T`, `FALSE`, `TRUE` or values from `na.strings` are converted to logical. Vectors containing optional whitespace followed by decimal constants representable as R integers or values from `na.strings` are converted to integer. Other vectors containing optional whitespace followed by other decimal or hexadecimal constants (see NumericConstants), or `NaN`, `Inf` or `infinity` (ignoring case) or values from `na.strings` are converted to numeric.

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`

[Package utils version 2.15.1 Index]