export.ofst-GRanges-method: Store GRanges / GAlignments object as .ofst

In ORFik: Open Reading Frames in Genomics

Description

A much faster way to store, load and use bam files.
.ofst is ORFik fast serialized object, an optimized format for coverage reads with cigar and replicate number. It uses the fst format as back-end: fst-package.
A .ofst ribo seq file can compress the information in a bam file from 5GB down to a few MB. This new files has super fast reading time, only a few seconds, instead of minutes. It also has random index access possibility of the file.
.ofst is represented as a data.frane format with minimum 4 columns:
1. chromosome
2. start (left most position)
3. strand (+, -, *)
4. width (not added if cigar exists)
5. cigar (not needed if width exists): (cigar # M's, match/mismatch total)
5. score: duplicates of that read
6. size: qwidth according to reference of read

If file is from GAlignmentPairs, it will contain a cigar1, cigar2 instead of cigar and start1 and start2 instead of start

Usage

## S4 method for signature 'GRanges'
export.ofst(x, file, ...)

Arguments

x	a GRanges, GAlignments or GAlignmentPairs object
file	a character, location on disc (full path)
...	additional arguments for write_fst

Details

Other columns can be named whatever you want and added to meta columns. Positions are 1-based, not 0-based as .bed. Import with import.ofst

Value

NULL, object saved to disc

Examples

## GRanges
gr <- GRanges("1:1-3:-")
# export.ofst(gr, file = "path.ofst")
## GAlignment
# Make input data.frame
df <- data.frame(seqnames = "1", cigar = "3M", start = 1L, strand = "+")
ga <- ORFik:::getGAlignments(df)
# export.ofst(ga, file = "path.ofst")

ORFik documentation built on March 27, 2021, 6 p.m.