laf-package: Fast access to large ASCII files
Description
The package provides methods for fast and efficient access of large ASCII
files (fixed width and csv files). It is assumed that the files are too large
to be read into memory completely. The package therefore contains methods for
blockwise processing of these files and methods for reading subsets of data
(rows and/or columns) from these files.Details
The basis of the package is the laf class. Objects of type laf
contain a reference to a file together with information such as column types,
columns widths etc. These objects can be ceated with the functions:
laf_open_fwf and laf_open_csv. After the objects
are created they can be used in two ways. First, the objects can be indexed as
one would a data.frame. Second, the file can be processed in a
blockwise fashion. Block after block is read in and processed. This can be
done using the following methods:
[object Object],[object Object],[object Object],[object Object]