tabula (version 1.3.0)

FrequencyMatrix-class: Frequency matrix

Description

An S4 class to represent a relative frequency matrix.

Slots

total

A numeric vector.

Get and set

In the code snippets below, x is a FrequencyMatrix object.

get_id(x)

Get the unique ID of x.

get_totals(x)

Get the row sums (counts) of x.

Matrix ID

When a matrix is first created, an identifier is generated (UUID v4). This ID is preserved when coercing to another class. Thus, the object ID is unique within the same class, but two objects of different classes can have the same ID. This makes it possible to identify objects representing the same initial data and associate them with the results of specific computations (e. g. seriation).

Access

In the code snippets below, x is a *Matrix object.

dim(x)

Returns the dimension of x.

nrow(x)

Returns the number of rows present in x.

ncol(x)

Returns the number of columns present in x.

dimnames(x), dimnames(x) <- value

Retrieves or sets the row dimnames of x according to value.

rownames(x), rownames(x) <- value

Retrieves or sets the row names of x according to value.

colnames(x), colnames(x) <- value

Retrieves or sets the column names of x according to value.

Subset

In the code snippets below, x is a *Matrix object.

x[i, j]

Extracts elements selected by subscripts i and j. Indices are numeric, integer or character vectors or empty (missing) or NULL. Numeric values are coerced to integer as by as.integer (and hence truncated towards zero). Character vectors will be matched to the name of the elements. An empty index (a comma separated blank) indicates that all entries in that dimension are selected. Returns an object of the same class as x.

x[[i]]

Extracts informations from a slot selected by subscript i. i should be one of "id" or NULL.

Details

To ensure data integrity, a FrequencyMatrix can only be created by coercion from a '>CountMatrix (see examples).

See Also

'>NumericMatrix, '>SpaceTime

Other abundance matrix: CountMatrix-class, OccurrenceMatrix-class

Other matrix class: CountMatrix-class, IncidenceMatrix-class, LogicalMatrix-class, Matrix-class, NumericMatrix-class, OccurrenceMatrix-class, SimilarityMatrix-class

Examples

# NOT RUN {
## Create a count data matrix
A1 <- CountMatrix(data = sample(0:10, 100, TRUE),
                  nrow = 10, ncol = 10, byrow = TRUE)

## Access
get_id(A1)
dim(A1) # Get the matrix dimensions
colnames(A1) # Get the column names
colnames(A1) <- letters[11:20] # Set the column names
rownames(A1) # Get the rownames
rownames(A1) <- LETTERS[1:10] # Set the row names

## Subset
A1[["id"]] # Get the matrix ID
A1[, ] # Get all values
A1[1, ] # Get the first row
A1[c("A", "B", "C"), ] # Get the first three rows
A1[c("A", "B", "C"), 1] # Get the first three rows of the first column
A1[, 1, drop = FALSE] # Get the first column

## Coerce counts to frequencies
B <- as_frequency(A1)
## Row sums are internally stored before coercing to a frequency matrix
get_totals(B) # Get row sums
## This allows to restore the source data
A2 <- as_count(B)
all(A1 == A2)
# }