textreg (version 0.1.5)

sample.fragments: Sample fragments of text to contextualize a phrase.

Description

Take a phrase, a labeling and a corpus and return text fragments containing that phrase.

Grab all phrases and then give sample of N from positive class and N from negative class. Sampling is to first sample from documents and then sample a random phrase from each of those documents.

Usage

sample.fragments(phrases, labeling, corp, N = 10, char.before = 80,
  char.after = char.before, metainfo = NULL)

Arguments

phrases

Phrases to examine (a list of strings)

labeling

-- a vector of the same length as the corpus

corp

Corpus object (tm package Corpus object)

N

size of sample to make.

char.before

Number of characters of document to pull before phrase to give context.

char.after

As above, but trailing characters. Defaults to char.before value.

metainfo

-- extra string to add to the printout for clarity if many such printouts are being generated.

See Also

Other sample.fragments: is.fragment.sample, print.fragment.sample

Examples

# NOT RUN {
library( tm )
data( bathtub )
sample.fragments( "bathtub", meta(bathtub)$meth.chl, bathtub )
# }