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LaF (version 0.8.4)

Fast Access to Large ASCII Files

Description

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.

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Install

install.packages('LaF')

Monthly Downloads

775

Version

0.8.4

License

GPL-3

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Maintainer

Last Published

March 23rd, 2020

Functions in LaF (0.8.4)

determine_nlines

Determine number of lines in a text file
current_line

Get the current line in the file
get_lines

Read in specified lines from a text file
close,laf-method

Close the connection to the Large File
[,laf-method

Read records from a large file object into R
read_dm

Read and write data models for LaF
goto

Go to specified line in the file
detect_dm_csv

Automatically detect data models for CSV-files
begin

Go to the beginning of the file
[[,laf-method

Select a column from a LaF object
laf_open_fwf

Create a connection to a fixed width file.
names,laf-method

Get and set the names of the columns in a Large File object
ncol,laf-method

Get the number of columns in a Large File object
read_dm_blaise

Read in Blaise data models
process_blocks

Blockwise processing of file
levels,laf-method

Get and change the levels of the column in a Large File object
next_block

Read the next block of data from a file.
laf-class

Large File object
laf_column-class

Column of a Large File Object
nrow,laf-method

Get the number of rows in 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 separated value (CSV) file.
show,laf-method

Print the Large File object to screen
colsum

Calculate simple statistics of column
read_lines

Read lines from the file
sample_lines

Read in random lines from a text file