bdgetDim_hdf5

bdgetDim_hdf5

HDF5_IO_MANAGEMENT

1 Description

Retrieves the dimensions (number of rows and columns) of a dataset stored in an HDF5 file.

2 Usage

bdgetDim_hdf5(filename, dataset)

3 Arguments

Parameter	Description
`filename`	Character string. Path to the HDF5 file.
`dataset`	Character string. Full path to the dataset within the HDF5 file (e.g., “group/subgroup/dataset”).

4 Value

Integer vector of length 2 containing: - [1] Number of rows - [2] Number of columns

5 Details

This function provides efficient access to dataset dimensions in HDF5 files. Key features: - Dimension information: - Number of rows - Number of columns - Implementation features: - Safe HDF5 file operations - Memory-efficient implementation - Comprehensive error handling - Read-only access to files

The function opens the HDF5 file in read-only mode to ensure data safety.

6 Examples

Code

library(BigDataStatMeth)

# Create a test HDF5 file
fn <- "test.hdf5"
X <- matrix(rnorm(100), 10, 10)

# Save matrix to HDF5
bdCreate_hdf5_matrix(fn, X, "data", "matrix1",
                     overwriteFile = TRUE)

# Get dimensions
dims <- bdgetDim_hdf5(fn, "data/matrix1")
print(paste("Rows:", dims[1]))
print(paste("Columns:", dims[2]))

# Cleanup
if (file.exists(fn)) {
  file.remove(fn)
}

7 See Also

bdgetDatasetsList_hdf5 for listing available datasets
bdCreate_hdf5_matrix for creating HDF5 matrices

---
title: "bdgetDim_hdf5"
subtitle: "bdgetDim_hdf5"
---

<span class="category-badge hdf5_io_management">HDF5_IO_MANAGEMENT</span>

## Description

Retrieves the dimensions (number of rows and columns) of a dataset stored in
an HDF5 file.

## Usage

```r
bdgetDim_hdf5(filename, dataset)
```
## Arguments

::: {.param-table}
| Parameter | Description |
|-----------|-------------|
| `filename` | Character string. Path to the HDF5 file. |
| `dataset` | Character string. Full path to the dataset within the HDF5 file   (e.g., "group/subgroup/dataset").  |
:::

## Value

::: {.return-value}
Integer vector of length 2 containing:
  - \[1\] Number of rows
  - \[2\] Number of columns

:::
## Details

This function provides efficient access to dataset dimensions in HDF5 files.
Key features:
- Dimension information:
  - Number of rows
  - Number of columns
- Implementation features:
  - Safe HDF5 file operations
  - Memory-efficient implementation
  - Comprehensive error handling
  - Read-only access to files

The function opens the HDF5 file in read-only mode to ensure data safety.


## Examples

```{r}
#| eval: false
#| code-fold: show

library(BigDataStatMeth)

# Create a test HDF5 file
fn <- "test.hdf5"
X <- matrix(rnorm(100), 10, 10)

# Save matrix to HDF5
bdCreate_hdf5_matrix(fn, X, "data", "matrix1",
                     overwriteFile = TRUE)

# Get dimensions
dims <- bdgetDim_hdf5(fn, "data/matrix1")
print(paste("Rows:", dims[1]))
print(paste("Columns:", dims[2]))

# Cleanup
if (file.exists(fn)) {
  file.remove(fn)
}
```

## See Also

::: {.see-also}
- [bdgetDatasetsList_hdf5](bdgetDatasetsList_hdf5.html) for listing available datasets
- [bdCreate_hdf5_matrix](bdCreate_hdf5_matrix.html) for creating HDF5 matrices

:::