srduplicated {ShortRead} | R Documentation

## Order, sort, and find duplicates in XStringSet objects

### Description

These generics order, rank, sort, and find duplicates in short read objects, including fastq-encoded qualities. `srorder`, `srrank` and `srsort` differ from the default functions `rank`, `order` and `sort` in that sorting is based on an internally-defined order rather than, e.g., the order implied by `LC_COLLATE`.

### Usage

    srorder(x, ...)
    srrank(x, ...)
    srsort(x, ...)
    srduplicated(x, ...)

### Arguments

`x` | The object to be sorted, ranked, ordered, or to have duplicates identified; see the examples below for objects for which methods are defined.
`...` | Additional arguments available for use by methods; usually ignored.

### Details

Unlike `sort` and friends, the implementation does not preserve order of duplicated elements. Like `duplicated`, one element in each set of duplicates is marked as `FALSE`.

`srrank` settles ties using the “min” criterion described in `rank`, i.e., identical elements are ranked equal to the rank of the first occurrence of the sorted element.

The following methods are defined, in addition to methods described in class-specific documentation:

srsort

  `signature(x = "XStringSet")`:

srorder

  `signature(x = "XStringSet")`:

srduplicated

  `signature(x = "XStringSet")`:

  Apply `srorder`, `srrank`, `srsort`, `srduplicated` to `XStringSet` objects such as those returned by `sread`.

srsort

  `signature(x = "ShortRead")`:

srorder

  `signature(x = "ShortRead")`:

srduplicated

  `signature(x = "ShortRead")`:

  Apply `srorder`, `srrank`, `srsort`, `srduplicated` to `XStringSet` objects to the `sread` component of `ShortRead` and derived objects.

### Value

The functions return the following values:

`srorder` | An integer vector the same length as `x`, containing the indices that will bring `x` into sorted order.
`srrank` | An integer vector the same length as `x`, containing the rank of each seqeunce when sorted.
`srsort` | An instance of `x` in sorted order.
`srduplicated` | A logical vector the same length as `x` indicating whether the indexed element is already present. Note that, like `duplicated`, subsetting `x` using the result returned by `!srduplicated(x)` includes one representative from each set of duplicates.

### Author(s)

Martin Morgan <mtmorgan@fhcrc.org>

### Examples

    showMethods("srsort")
    showMethods("srorder")
    showMethods("srduplicated")

    sp <- SolexaPath(system.file('extdata', package='ShortRead'))
    rfq <- readFastq(analysisPath(sp), pattern="s_1_sequence.txt")

    sum(srduplicated(sread(rfq)))
    srsort(sread(rfq))
    srsort(quality(rfq))

[Package ShortRead version 1.50.0 Index]