tm (version 0.5-10)

readTabular: Read In a Text Document

Description

Return a function which reads in a text document from a tabular data structure (like a data frame or a list matrix) with knowledge about its internal structure and possible available metadata as specified by a so-called mapping.

Usage

readTabular(mapping)

Arguments

mapping

A named list of characters. The constructed reader will map each character entry to the content or meta datum of the text document as specified by the named list entry. Valid names include Content to acce

Value

• A function with the signature elem, language, id: [object Object],[object Object],[object Object] The function returns a PlainTextDocument representing the text and meta data extracted from elem$content.

Details

Formally this function is a function generator, i.e., it returns a function (which reads in a text document) with a well-defined signature, but can access passed over arguments (e.g., the mapping) via lexical scoping.

See Also

Vignette 'Extensions: How to Handle Custom File Formats'.

getReaders to list available reader functions.

Examples

df <- data.frame(contents = c("content 1", "content 2", "content 3"),
                 title    = c("title 1"  , "title 2"  , "title 3"  ),
                 authors  = c("author 1" , "author 2" , "author 3" ),
                 topics   = c("topic 1"  , "topic 2"  , "topic 3"  ),
                 stringsAsFactors = FALSE)
m <- list(Content = "contents", Heading = "title",
          Author = "authors", Topic = "topics")
myReader <- readTabular(mapping = m)
ds <- DataframeSource(df)
elem <- getElem(stepNext(ds))
(result <- myReader(elem, language = "en", id = "id1"))
meta(result)