Skip to contents

Switch matrix to table

Source: R/RcppExports.R
matrix_to_table.Rd

Switch matrix to table

Usage

matrix_to_table(
  matrix,
  row_names = NULL,
  col_names = NULL,
  threshold = 0,
  keep_zero = TRUE
)

Arguments

matrix

A matrix.

row_names

Character vector of row names to filter by.

col_names

Character vector of column names to filter by.

threshold

The threshold for filtering values based on absolute values. Defaults to 0.

keep_zero

Whether to keep zero values in the table. Defaults to true for backward compatibility.

Value

A table with three columns: row, col, and value.

Details

With keep_zero = FALSE, sparse input is traversed through its stored entries and implicit zeros are not materialized. The backward-compatible default, keep_zero = TRUE, emits every selected matrix position, including implicit sparse zeros, and therefore requires time and output memory proportional to the selected nrow * ncol. When zeros are omitted, an all-zero row or column is absent from the table and cannot be reconstructed by table_to_matrix() without separate dimension metadata.

See also

table_to_matrix

Examples

test_matrix <- simulate_sparse_matrix(10, 10)
colnames(test_matrix) <- paste0("c", 1:10)
rownames(test_matrix) <- paste0("r", 1:10)
table <- matrix_to_table(test_matrix)
matrix_new <- table_to_matrix(table)
test_matrix <- test_matrix[rownames(matrix_new), colnames(matrix_new)] |>
  as_matrix()
identical(test_matrix, matrix_new)
#> [1] TRUE

matrix_to_table(
  test_matrix,
  threshold = 2
)
#>   row col value
#> 1  r8  c7     2
#> 2  r9  c4     2

matrix_to_table(
  test_matrix,
  row_names = c("r1", "r2"),
  col_names = c("c1", "c2")
)
#>   row col value
#> 1  r1  c1     1
#> 2  r1  c2     0
#> 3  r2  c1     0
#> 4  r2  c2     0