laf-class: Large File object

In LaF: Fast Access to Large ASCII Files

Description

A Large File object. This is a reference to a dataset on disk. The data itself is not read into memory (yet). This can be done by the methods for blockwise processing or by indexing the object as a data.frame. The code has been optimised for fast access.

Objects from the Class

Objects can be created by opening a file using one of the methods laf_open_csv or laf_open_fwf. These create a reference to either a CSV file or a fixed width file. The data in these files can either be accessed using blockwise operations using the methods begin, next_block and goto. Or by indexing the laf object as you would a data.frame. In the following example a CSV file is opened and its first column (of type integer) is read into memory:

   laf <- laf_open_csv("file.csv", column_types=c("integer", "double"))
   data <- laf[ , 1]
 

LaF documentation built on March 26, 2020, 6:59 p.m.