Corpus Data Frame

Create or test for corpus objects.

corpus_frame(..., row.names = NULL, filter = NULL)

as_corpus_frame(x, filter = NULL, ..., row.names = NULL)

is_corpus_frame(x)

Arguments

...	data frame columns for corpus_frame; further arguments passed to as_corpus_text from as_corpus_frame.
row.names	character vector of row names for the corpus object.
filter	text filter object for the "text" column in the corpus object.
x	object to be coerced or tested.

Details

These functions create or convert another object to a corpus object. A corpus object is just a data frame with special functions for printing, and a column names "text" of type "corpus_text".

corpus has similar semantics to the data.frame function, except that string columns do not get converted to factors.

as_corpus_frame converts another object to a corpus data frame object. By default, the method converts x to a data frame with a column named "text" of type "corpus_text", and sets the class attribute of the result to c("corpus_frame", "data.frame").

is_corpus_frame tests whether x is a data frame with a column named "text" of type "corpus_text".

as_corpus_frame is generic: you can write methods to handle specific classes of objects.

Value

corpus_frame creates a data frame with a column named "text" of type "corpus_text", and a class attribute set to c("corpus_frame", "data.frame").

as_corpus_frame attempts to coerce its argument to a corpus data frame object, setting the row.names and calling as_corpus_text on the "text" column with the filter and ... arguments.

is_corpus_frame returns TRUE or FALSE depending on whether its argument is a valid corpus object or not.

See also

corpus-package, print.corpus_frame, corpus_text, read_ndjson.

Examples

# convert a data frame:
emoji <- data.frame(text = sapply(0x1f600 + 1:30, intToUtf8),
                    stringsAsFactors = FALSE)
as_corpus_frame(emoji)
#>    text
#> 1  😁​  
#> 2  😂​  
#> 3  😃​  
#> 4  😄​  
#> 5  😅​  
#> 6  😆​  
#> 7  😇​  
#> 8  😈​  
#> 9  😉​  
#> 10 😊​  
#> 11 😋​  
#> 12 😌​  
#> 13 😍​  
#> 14 😎​  
#> 15 😏​  
#> 16 😐​  
#> 17 😑​  
#> 18 😒​  
#> 19 😓​  
#> 20 😔​  
#> ⋮  (30 rows total)

# construct directly (no need for stringsAsFactors = FALSE):
corpus_frame(text = sapply(0x1f600 + 1:30, intToUtf8))
#>    text
#> 1  😁​  
#> 2  😂​  
#> 3  😃​  
#> 4  😄​  
#> 5  😅​  
#> 6  😆​  
#> 7  😇​  
#> 8  😈​  
#> 9  😉​  
#> 10 😊​  
#> 11 😋​  
#> 12 😌​  
#> 13 😍​  
#> 14 😎​  
#> 15 😏​  
#> 16 😐​  
#> 17 😑​  
#> 18 😒​  
#> 19 😓​  
#> 20 😔​  
#> ⋮  (30 rows total)
    
# convert a character vector:
as_corpus_frame(c(a = "goodnight", b = "moon")) # keeps names
#>   text     
#> a goodnight
#> b moon     
as_corpus_frame(c(a = "goodnight", b = "moon"), row.names = NULL) # drops names
#>   text     
#> a goodnight
#> b moon