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Convert a Vector, Matrix or Data Frame Into Numeric Values If Possible

asNumericIfPossible.Rd

This function converts vectors and matrices of all kinds to numeric. The function can also be used to convert all columns of a data.frame to class numeric for which this conversion is possible i.e. without creating NA when it fails. Non-convertible columns are maintained.

Usage

asNumericIfPossible(x, maintain.factor.scores = TRUE, force.string = TRUE,
transform.factors = TRUE, varName = NULL)

Arguments

x

A vector or data frame which should be converted.

maintain.factor.scores

Logical: If TRUE, conversion of the factor levels is attempted (like in as.numeric(as.character(f))). If FALSE, the internal codes of the factor are returned (like in as.numeric(f)). See 'Details'. This argument is only evaluated if transform.factors = TRUE.

force.string

Logical indicating whether columns should be force to numeric, even if NAs are induced. If FALSE, affected columns are maintained. If TRUE, conversion is forced.

transform.factors

Logical indicating whether columns of class factor should be converted. If FALSE, columns of class factor are maintained. If TRUE, conversion of factors is attempted.

varName

Optional: Name of the corresponding variable. Doesn't have to be changed by user.

Details

In R, factors may represent ordered categories or categorical variables. Depending on the meaning of the variable, a conversion of the nominal values (of a factor variable) to numeric values may be desirable or not. The arguments transform.factors and maintain.factor.scores specify if and how factor variables should be treated. See examples.

Author

Sebastian Weirich, Karoline Sachse, Benjamin Becker

Examples

dat <- data.frame(X1 = c("1",NA,"0"), X2 = c("a",NA,"b"),
                  X3 = c(TRUE,FALSE,FALSE), X4 = as.factor(c("a",NA,"b")),
                  X5 = as.factor(c("5","6","7")), stringsAsFactors = FALSE)
str(dat)
#> 'data.frame':	3 obs. of  5 variables:
#>  $ X1: chr  "1" NA "0"
#>  $ X2: chr  "a" NA "b"
#>  $ X3: logi  TRUE FALSE FALSE
#>  $ X4: Factor w/ 2 levels "a","b": 1 NA 2
#>  $ X5: Factor w/ 3 levels "5","6","7": 1 2 3
asNumericIfPossible(dat)
#> Warning: 'X2' has been coerced to numeric, NAs have been induced.
#> Warning: 'X4' has been coerced to numeric, NAs have been induced.
#>   X1 X2 X3 X4 X5
#> 1  1 NA  1 NA  5
#> 2 NA NA  0 NA  6
#> 3  0 NA  0 NA  7
asNumericIfPossible(dat, transform.factors=TRUE,
                      maintain.factor.scores=FALSE)
#> Warning: 'X2' has been coerced to numeric, NAs have been induced.
#>   X1 X2 X3 X4 X5
#> 1  1 NA  1  1  1
#> 2 NA NA  0 NA  2
#> 3  0 NA  0  2  3
asNumericIfPossible(dat, transform.factors=TRUE,
                      maintain.factor.scores=TRUE)
#> Warning: 'X2' has been coerced to numeric, NAs have been induced.
#> Warning: 'X4' has been coerced to numeric, NAs have been induced.
#>   X1 X2 X3 X4 X5
#> 1  1 NA  1 NA  5
#> 2 NA NA  0 NA  6
#> 3  0 NA  0 NA  7