dfm-class: Virtual class "dfm" for a document-feature matrix

In quanteda: Quantitative Analysis of Textual Data

Virtual class "dfm" for a document-feature matrix

Description

The dfm class of object is a type of Matrix-class object with additional slots, described below. quanteda uses two subclasses of the dfm class, depending on whether the object can be represented by a sparse matrix, in which case it is a dfm class object, or if dense, then a dfmDense object. See Details.

Usage

## S4 method for signature 'dfm'
t(x)

## S4 method for signature 'dfm'
colSums(x, na.rm = FALSE, dims = 1, ...)

## S4 method for signature 'dfm'
rowSums(x, na.rm = FALSE, dims = 1, ...)

## S4 method for signature 'dfm'
colMeans(x, na.rm = FALSE, dims = 1, ...)

## S4 method for signature 'dfm'
rowMeans(x, na.rm = FALSE, dims = 1, ...)

## S4 method for signature 'dfm,numeric'
Arith(e1, e2)

## S4 method for signature 'numeric,dfm'
Arith(e1, e2)

## S4 method for signature 'dfm,index,index,missing'
x[i, j, ..., drop = TRUE]

## S4 method for signature 'dfm,index,index,logical'
x[i, j, ..., drop = TRUE]

## S4 method for signature 'dfm,missing,missing,missing'
x[i, j, ..., drop = TRUE]

## S4 method for signature 'dfm,missing,missing,logical'
x[i, j, ..., drop = TRUE]

## S4 method for signature 'dfm,index,missing,missing'
x[i, j, ..., drop = TRUE]

## S4 method for signature 'dfm,index,missing,logical'
x[i, j, ..., drop = TRUE]

## S4 method for signature 'dfm,missing,index,missing'
x[i, j, ..., drop = TRUE]

## S4 method for signature 'dfm,missing,index,logical'
x[i, j, ..., drop = TRUE]

Arguments

x	the dfm object
na.rm	if TRUE, omit missing values (including NaN) from the calculations
dims	ignored
...	additional arguments not used here
e1	first quantity in an Arith operation for dfm
e2	second quantity in an Arith operation for dfm
i	document names or indices for documents to extract.
j	feature names or indices for documents to extract.

Details

The dfm class is a virtual class that will contain dgCMatrix-class.

Slots

weightTf

the type of term frequency weighting applied to the dfm. Default is "frequency", indicating that the values in the cells of the dfm are simple feature counts. To change this, use the dfm_weight() method.

weightFf

the type of document frequency weighting applied to the dfm. See docfreq().

smooth

a smoothing parameter, defaults to zero. Can be changed using the dfm_smooth() method.

Dimnames

These are inherited from Matrix-class but are named docs and features respectively.

See Also

dfm

Examples

# dfm subsetting
dfmat <- dfm(tokens(c("this contains lots of stopwords",
                  "no if, and, or but about it: lots",
                  "and a third document is it"),
                remove_punct = TRUE))
dfmat[1:2, ]
dfmat[1:2, 1:5]

quanteda documentation built on Sept. 11, 2024, 6:08 p.m.