R: Span objects

Span {NLP} | R Documentation

## Span objects

### Description

Creation and manipulation of span objects.

### Usage

    Span(start, end)
    as.Span(x)
    is.Span(x)

### Arguments

`start, end` | integer vectors giving the start and end positions of the spans.
`x` | an R object.

### Details

A single span is a pair with “slots” ‘start’ and ‘end’, giving the start and end positions of the span.

Span objects provide sequences (allowing positional access) of single spans. They have class `"Span"`. Span objects can be coerced to annotation objects via `as.Annotation()` (which of course is only appropriate provided that the spans are character spans of the natural language text being annotated), and annotation objects can be coerced to span objects via `as.Span()` (giving the character spans of the annotations).

Subscripting span objects via `[` extracts subsets of spans; subscripting via `$` extracts integer vectors with the sequence of values of the named slot.

There are several additional methods for class `"Span"`: `print()` and `format()`; `c()` combines spans (or objects coercible to these using `as.Span()`), and `as.list()` and `as.data.frame()` coerce, respectively, to lists (of single span objects) and data frames (with spans and slots corresponding to rows and columns). Finally, one can add a scalar and a span object (resulting in shifting the start and end positions by the scalar).

`Span()` creates span objects from the given sequences of start and end positions, which must have the same length.

`as.Span()` coerces to span objects, with a method for annotation objects.

`is.Span()` tests whether an object inherits from class `"Span"` (and hence returns `TRUE` for both span and annotation objects).

### Value

For `Span()` and `as.Span()`, a span object (of class `"Span"`).

For `is.Span()`, a logical.

[Package NLP version 0.1-10 Index]