long2sparse

Convert Long-Format Data Frame to Sparse Matrix

Usage

long2sparse(
  long,
  row_names_from,
  col_names_from,
  values_from,
  unique_rows = NULL,
  unique_cols = NULL,
  symmetric = FALSE
)

Arguments

long

A data frame in long format with at least three columns: row ID, column ID, and value.

row_names_from

Name of the column in `long` to use as row names in the output.

col_names_from

Name of the column in `long` to use as column names in the output.

values_from

Name of the column in `long` to use as cell values in the output matrix.

unique_rows

Optional character or factor vector defining the full set and order of row names.

unique_cols

Optional character or factor vector defining the full set and order of column names.

symmetric

Logical. If `TRUE`, creates a symmetric matrix by adding reversed entries (default: FALSE).

Value

A sparse matrix of class `dgCMatrix` with row and column names.

Details

Converts a long-format data frame representing pairwise relationships into a sparse matrix (`dgCMatrix`), with optional symmetry enforcement and customizable row/column ordering.

Examples

long_df <- data.frame(from = c("A", "B"), to = c("B", "C"), value = c(1, 2))
spmat <- long2sparse(long_df, "from", "to", "value")
print(spmat)
#> 2 x 2 sparse Matrix of class "dgCMatrix"
#>   B C
#> A 1 .
#> B . 2