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Get the Total Length of an HDF5 Object or Attribute

Source: R/info.r
h5_length.Rd

Behaves like length() for R objects.

  • For Compound Datasets (data.frames), this is the number of columns.

  • For Datasets and Attributes, this is the product of all dimensions (total number of elements).

  • For Groups, this is the number of objects directly contained in the group.

  • Scalar datasets or attributes return 1.

Usage

h5_length(file, name, attr = NULL)

Arguments

file

The path to the HDF5 file.

name

The full path of the object (group or dataset).

attr

The name of an attribute to check. If provided, the length of the attribute is returned.

Value

An integer representing the total length (number of elements).

Examples

file <- tempfile(fileext = ".h5")

h5_write(1:100, file, "my_vec")
h5_length(file, "my_vec") # 100
#> [1] 100

h5_write(mtcars, file, "my_df")
h5_length(file, "my_df") # 11 (ncol(mtcars))
#> [1] 11

h5_write(as.matrix(mtcars), file, "my_mtx")
h5_length(file, "my_mtx") # 352 (prod(dim(mtcars)))
#> [1] 352

h5_length(file, "/") # 3
#> [1] 3

unlink(file)