h5lite (version 2.0.0.2)

h5_exists: Check if an HDF5 File, Object, or Attribute Exists

Description

Safely checks if a file, an object within a file, or an attribute on an object exists.

Usage

h5_exists(file, name = "/", attr = NULL, assert = FALSE)

Value

A logical value: TRUE if the target exists and is valid, FALSE otherwise.

Arguments

file

Path to the file.

name

The full path of the object to check (e.g., "/data/matrix"). Defaults to "/" to test file validity.

attr

The name of an attribute to check. If provided, the function tests for the existence of this attribute on name.

assert

Logical. If TRUE and the target does not exist, the function will stop with an informative error message instead of returning FALSE. Defaults to FALSE.

Details

This function provides a robust, error-free way to test for existence.

• Testing for a File: If name is / and attr is NULL, the function checks if file is a valid, readable HDF5 file.

• Testing for an Object: If name is a path (e.g., /data/matrix) and attr is NULL, the function checks if the specific object exists.

• Testing for an Attribute: If attr is provided, the function checks if that attribute exists on the specified object name.

See Also

h5_is_group(), h5_is_dataset()

Examples

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

h5_exists(file) # FALSE

h5_create_file(file)
h5_exists(file) # TRUE

h5_exists(file, "missing_object") # FALSE

h5_write(1:10, file, "my_ints")
h5_exists(file, "my_ints") # TRUE

h5_exists(file, "my_ints", "missing_attr") # FALSE

h5_write(1:10, file, "my_ints", attr = "my_attr")
h5_exists(file, "my_ints", "my_attr") # TRUE

unlink(file)