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Validate Corpus Data Frame Object

Source: R/validators.R
tif_is_corpus_df.Rd

A valid data frame corpus object is an object that least two columns. One column must be called doc_id and be a character vector with UTF-8 encoding. Document ids must be unique. There must also be a column called text and must also be a character vector in UTF-8 encoding. Each individual document is represented by a single row in the data frame. Addition document-level metadata columns and corpus level attributes are allowed but not required.

Usage

tif_is_corpus_df(corpus, warn = FALSE)

Arguments

corpus

a corpus object to test for validity

warn

logical. Should the function produce a verbose warning for the condition for which the validation fails. Useful for testing.

Value

a logical vector of length one indicating whether the input is a valid corpus

Details

The tests are run sequentially and the function returns, with a warning if the warn flag is set, on the first test that fails. We use this implementation because some tests may fail entirely or be meaningless if the prior ones are note passed. For example, if the corpus object does not have a variable named "text" it does not make sense to check whether this column is a character vector.

Examples

corpus <- data.frame(doc_id = c("doc1", "doc2", "doc3"),
                     text = c("Aujourd'hui, maman est morte.",
                      "It was a pleasure to burn.",
                      "All this happened, more or less."),
                     stringsAsFactors = FALSE)

tif_is_corpus_df(corpus)
#> [1] TRUE

corpus$author <- c("Camus", "Bradbury", "Vonnegut")
tif_is_corpus_df(corpus)
#> [1] TRUE