indexing: Read records from a large file object into R
In LaF: Fast Access to Large ASCII Files

When a connection is opened to a "laf" object; this object can then be indexed roughly as one would a data.frame.

## S4 method for signature 'laf'
x[i, j, drop]

## S4 method for signature 'laf_column'
x[i, j, drop]

`x`	an object of type `"laf"` or `"laf_column"`.
`i`	an logical or numeric vector with indices. The rows which should be selected.
`j`	a numeric vector with the columns to select.
`drop`	a logical indicating whether or not to convert the result to a vector when only one column is selected. As in when indexing a `data.frame`.