big_read {bigstatsr} | R Documentation |
Read a file as FBM
Description
Read a file as a Filebacked Big Matrix by using package bigreadr.
For a mini-tutorial, please see this vignette.
Usage
big_read(
file,
select,
filter = NULL,
type = c("double", "float", "integer", "unsigned short", "unsigned char", "raw"),
backingfile = drop_ext(file),
...
)
Arguments
file |
File to read.
|
select |
Indices of columns to read (sorted).
The length of select will be the number of columns of the resulting FBM.
|
filter |
Vector used to subset the rows of each data frame.
|
type |
Type of the Filebacked Big Matrix (default is double ). Either
-
"double" (double precision – 64 bits)
-
"float" (single precision – 32 bits)
-
"integer"
-
"unsigned short" : can store integer values from 0 to 65535.
It has vocation to become the basis for a FBM.code65536 .
-
"raw" or "unsigned char" : can store integer values from 0 to 255.
It is the basis for class FBM.code256 in order to
access 256 arbitrary different numeric values.
It is used in package bigsnpr.
|
backingfile |
Path to the file storing the FBM data on disk.
An extension ".bk" will be automatically added.
Default uses file without its extension.
|
... |
Arguments passed on to bigreadr::big_fread2
nb_parts Number of parts in which to split reading (and transforming).
Parts are referring to blocks of selected columns.
Default uses part_size to set a good value.
skip Number of lines to skip at the beginning of file .
progress Show progress? Default is FALSE .
part_size Size of the parts if nb_parts is not supplied.
Default is 500 * 1024^2 (500 MB).
|
Value
A Filebacked Big Matrix of type type
with length(select)
columns.
[Package
bigstatsr version 1.5.12
Index]