h5readBlock {h5vc} | R Documentation

## h5readBlock

### Description

A simple access function for extracting a single block of data from a tally file, use `h5dapply` for applying functions on multiple blocks / extracting multiple blocks form a tally file.

### Usage

    h5readBlock( filename, group, names, dims, range, samples = NULL, sampleDimMap = .sampleDimMap, verbose = FALSE )

### Arguments

`filename` | The name of a tally file to process
`group` | The name of a group in that tally file
`names` | The names of the datasets to extract, e.g. `c("Counts","Coverages")` - optional (defaults to all datasets)
`dims` | The dimension in which the block shall be extracted for each dataset in the same order as `names`, these should correspond to compatible dimensions between the datsets. - optional (defaults to the genomic position dimension)
`range` | The range along the specified dimensions which should be extracted
`samples` | Character vector of sample names - must match contents of sampleData stored in the `tallyFile`
`sampleDimMap` | A list mapping dataset names to their respective sample dimensions - default provides values for "Counts", "Coverages", "Deletions" and "Reference"
`verbose` | Boolean flag that controls the amount of messages being printed by `h5dapply`

### Details

This function extracts a block along the dimensions specified in `dims` (default: genomic position) from the datasets specified in `names` and returns it. The block is defined by the parameter `range`.

The function returns a `list` with one slot for each dataset specified in the `names` argument to containing the array corresponding to the specified block in the given dataset. Furthemore the slot `h5dapplyInfo` is reserved and contains another `list` with the following content:

`Blockstart` is an integer specifying the starting position of the current block (in the dimension specified by the `dims` argument to `h5dapply`)

`Blockend` is an integer specifying the end position of the current block (in the dimension specified by the `dims` argument to `h5dapply`)

`Datasets` Contains a `data.frame` as it is returned by `h5ls` listing all datasets present in the other slots of `data` with their group, name, dimensions, number of dimensions (`DimCount`) and the dimension that is used for splitting into blocks (`PosDim`)

`Group` contains the name of the group as specified by the `group` argument to `h5dapply`

### Value

A list with one entry per dataset and an additional slot `h5dapplyInfo` containing auxiliary information.

### Author(s)

Paul Pyl

### Examples

    library(h5vc) # loading the library
    tallyFile <- system.file( "extdata", "example.tally.hfs5", package = "h5vcData" )
    data <- h5readBlock( #extracting coverage, deletions and reference using h5dreadBlock
      filename = tallyFile,
      group = "/ExampleStudy/16",
      names = c( "Coverages", "Deletions", "Reference" ),
      range = c(29000000,29010000),
      verbose = TRUE
    )
    str(data)
    sampleData <- getSampleData( tallyFile, "/ExampleStudy/16" )
    #Subsetting by Sample
    sampleData <- sampleData[sampleData$Patient == "Patient8",]
    data <- h5readBlock( #extracting coverage, deletions and reference using h5dreadBlock
      filename = tallyFile,
      group = "/ExampleStudy/16",
      names = c( "Coverages", "Deletions", "Reference" ),
      range = c(29000000,29010000),
      samples = sampleData$Sample,
      verbose = TRUE
    )
    str(data)

[Package h5vc version 2.18.0 Index]