Check if an HDF5 File or Object Exists

Safely checks if a file is a valid HDF5 file or if a specific object (group or dataset) exists within a valid HDF5 file.

Usage

h5_exists(file, name = "/")

Arguments

file

Path to the file.

name

The full path of the object to check (e.g., "/data/matrix"). Defaults to "/", which tests if the file itself is a valid HDF5 file.

Value

A logical value: TRUE if the file/object exists and is valid, FALSE otherwise.

Details

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

• Testing for a File: If name is / (the default), the function checks if file is a valid, readable HDF5 file. It will return FALSE for non-existent files, non-HDF5 files, or corrupted files without raising an error.

• Testing for an Object: If name is a path (e.g., /data/matrix), the function first confirms the file is valid HDF5, and then checks if the specific object exists within it.

See also

h5_exists_attr(), h5_is_group(), h5_is_dataset()

Examples

file <- tempfile(fileext = ".h5")
h5_write(file, "my_data", 1:10)

# --- Test 1: Check for a specific object ---
h5_exists(file, "my_data") # TRUE
#> [1] TRUE
h5_exists(file, "nonexistent_data") # FALSE
#> [1] FALSE

# --- Test 2: Check for a valid HDF5 file ---
h5_exists(file) # TRUE
#> [1] TRUE
h5_exists(file, "/") # TRUE
#> [1] TRUE

# --- Test 3: Check invalid or non-existent files ---
h5_exists("not_a_real_file.h5") # FALSE
#> [1] FALSE

text_file <- tempfile()
writeLines("this is not hdf5", text_file)
h5_exists(text_file) # FALSE
#> [1] FALSE

# Check for an object in an invalid file (also FALSE)
h5_exists(text_file, "my_data") # FALSE
#> [1] FALSE

unlink(file)
unlink(text_file)