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Convert functional data back to tabular data formats

Source: R/convert.R
converters.Rd

Various converters to turn tfb- or tfd-vectors into data.frames or matrices, or even an actual R function.

Usage

# S3 method for class 'tf'
as.data.frame(x, row.names = NULL, optional = FALSE, unnest = FALSE, ...)

# S3 method for class 'tf'
as.matrix(x, arg, interpolate = FALSE, ...)

# S3 method for class 'tf'
as.function(x, ...)

Arguments

x

a tf object.

row.names

NULL or a character vector giving the row names for the data frame. Missing values are not allowed.

optional

not used.

unnest

if TRUE, the function will return a data.frame with the evaluated functions.

...

additional arguments to be passed to or from methods.

arg

a vector of argument values / evaluation points for x. Defaults to tf_arg(x) (so for x on irregular grids, this will be the union of all observed arg-values by default).

interpolate

should functions be evaluated (i.e., inter-/extrapolated) for values in arg for which no original data is available? Only relevant for the raw data class tfd, for which it defaults to FALSE. Basis-represented functional data tfb are always "interpolated".

Value

for as.data.frame.tf: if unnest is FALSE (default), a one-column data.frame with a tf-column containing x. if unnest is TRUE, a 3-column data frame with columns id (containing (unique) names of x or a numeric identifier if x is unnamed), arg, and value, with each row containing one function evaluation at the original arg-values.

for as.matrix.tf: a matrix with one row per function and one column per arg.

for as.function.tf: an R function with argument arg that evaluates x on arg and returns the list of function values

Examples

f <- tfd(sin(seq(0, 2 * pi, length.out = 11)), arg = seq(0, 1, length.out = 11))
as.data.frame(f)
#>             f
#> 1 ▄▇██▇▅▂▁▁▂▄
as.data.frame(f, unnest = TRUE)
#>    id arg         value
#> 1   1 0.0  0.000000e+00
#> 2   1 0.1  5.877853e-01
#> 3   1 0.2  9.510565e-01
#> 4   1 0.3  9.510565e-01
#> 5   1 0.4  5.877853e-01
#> 6   1 0.5  1.224647e-16
#> 7   1 0.6 -5.877853e-01
#> 8   1 0.7 -9.510565e-01
#> 9   1 0.8 -9.510565e-01
#> 10  1 0.9 -5.877853e-01
#> 11  1 1.0 -2.449294e-16
as.matrix(f)
#>      0       0.1       0.2       0.3       0.4          0.5        0.6
#> [1,] 0 0.5877853 0.9510565 0.9510565 0.5877853 1.224647e-16 -0.5877853
#>             0.7        0.8        0.9             1
#> [1,] -0.9510565 -0.9510565 -0.5877853 -2.449294e-16
#> attr(,"arg")
#>  [1] 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
fun <- as.function(f)
fun(c(0, 0.5, 1))
#> [[1]]
#> [1]  0.000000e+00  1.224647e-16 -2.449294e-16
#>