LaF: Fast access to large ASCII files

Methods for fast access to large ASCII files. Currently the following file formats are supported: comma separated format (csv) and fixed width format. It is assumed that the files are too large to fit into memory, although the package can also be used to efficiently access files that do fit into memory. Methods are provided to access and process files blockwise. Furthermore, an opened file can be accessed as one would an ordinary data.frame. The LaF vignette gives an overview of the functionality provided.

Author
Jan van der Laan
Date of publication
2015-01-28 20:27:18
Maintainer
Jan van der Laan <djvanderlaan@unrealizedtime.nl>
License
GPL-3
Version
0.6.2
URLs

View on CRAN

Man pages

begin
Go to the beginning of the file
cindexing
Select a column from a LaF object
close
Close the connection to the Large File
current_line
Get the current line in the file
datamodels
Read and write data models for LaF
detect_dm_csv
Automatically detect data models for CSV-files
determine_nlines
Determine number of lines in a text file
get_lines
Read in specified lines from a text file
goto
Go to specified line in the file
indexing
Read records from a large file object into R
laf-class
Large File object
laf_column-class
Column of a Large File Object
laf_open
Create a connection to a file using a data model.
laf_open_csv
Create a connection to a comma seperated value (CSV) file.
laf_open_fwf
Create a connection to a fixed width file.
levels
Get and change the levels of the column in a Large File...
names
Get the names of the columns in a Large File object
ncol
Get the number of columns in a Large File object
next_block
Read the next block of data from a file.
nrow
Get the number of rows in a Large File object
process_blocks
Blockwise processing of file
read_dm_blaise
Read in Blaise data models
read_lines
Read lines from the file
sample_lines
Read in random lines from a text file
show
Print a column of a Large File object to screen
stats
Calculate simple statistics of column

Files in this package

LaF
LaF/inst
LaF/inst/doc
LaF/inst/doc/LaF-benchmark.pdf
LaF/inst/doc/LaF-manual.pdf
LaF/inst/doc/LaF-manual.Rnw
LaF/inst/doc/LaF-benchmark.Rnw
LaF/inst/doc/LaF-manual.R
LaF/tests
LaF/tests/testthat
LaF/tests/testthat/test_fwf.R
LaF/tests/testthat/test_csv.R
LaF/tests/testthat/test_skip.R
LaF/tests/testthat/test_conversion.R
LaF/tests/testthat/test_stats.R
LaF/tests/testthat/test_trim.R
LaF/tests/testthat/test_levels.R
LaF/tests/testthat/test_meta.R
LaF/tests/test-all.R
LaF/src
LaF/src/Makevars
LaF/src/stringcolumn.h
LaF/src/LaF.cpp
LaF/src/conversion.h
LaF/src/fwfreader.h
LaF/src/csvreader.h
LaF/src/column.cpp
LaF/src/readermanager.cpp
LaF/src/stringcolumn.cpp
LaF/src/factorcolumn.h
LaF/src/csvreader.cpp
LaF/src/stats.cpp
LaF/src/intcolumn.cpp
LaF/src/doublecolumn.h
LaF/src/readermanager.h
LaF/src/factorcolumn.cpp
LaF/src/file.cpp
LaF/src/reader.h
LaF/src/fwfreader.cpp
LaF/src/column.h
LaF/src/reader.cpp
LaF/src/file.h
LaF/src/Makevars.win
LaF/src/textutils.cpp
LaF/src/intcolumn.h
LaF/src/doublecolumn.cpp
LaF/src/conversion.cpp
LaF/NAMESPACE
LaF/NEWS
LaF/R
LaF/R/generics.R
LaF/R/meta.R
LaF/R/textutils.R
LaF/R/utility.R
LaF/R/read_dm_blaise.R
LaF/R/laf_column.R
LaF/R/stats.R
LaF/R/open.R
LaF/R/types.R
LaF/R/laf.R
LaF/vignettes
LaF/vignettes/LaF-benchmark.Rnw.orig
LaF/vignettes/LaF-manual.Rnw
LaF/vignettes/LaF-benchmark.Rnw
LaF/MD5
LaF/build
LaF/build/vignette.rds
LaF/DESCRIPTION
LaF/man
LaF/man/current_line.Rd
LaF/man/datamodels.Rd
LaF/man/get_lines.Rd
LaF/man/read_dm_blaise.Rd
LaF/man/show.Rd
LaF/man/laf_open_fwf.Rd
LaF/man/read_lines.Rd
LaF/man/names.Rd
LaF/man/determine_nlines.Rd
LaF/man/laf_column-class.Rd
LaF/man/begin.Rd
LaF/man/nrow.Rd
LaF/man/indexing.Rd
LaF/man/detect_dm_csv.Rd
LaF/man/next_block.Rd
LaF/man/levels.Rd
LaF/man/stats.Rd
LaF/man/cindexing.Rd
LaF/man/laf-class.Rd
LaF/man/goto.Rd
LaF/man/sample_lines.Rd
LaF/man/process_blocks.Rd
LaF/man/ncol.Rd
LaF/man/close.Rd
LaF/man/laf_open_csv.Rd
LaF/man/laf_open.Rd