R: Create a sparse matrix from row names, column names, and...

cast_sparse {tidytext} | R Documentation

## Create a sparse matrix from row names, column names, and values in a table.

### Description

Create a sparse matrix from row names, column names, and values in a table.

### Usage

    cast_sparse(data, row, column, value)

### Arguments

`data` | A tbl
`row` | A bare column name to use as row names in sparse matrix
`column` | A bare column name to use as column names in sparse matrix
`value` | A bare column name to use as sparse matrix values, default 1

### Details

Note that cast_sparse ignores groups in a grouped tbl_df.

### Value

A sparse Matrix object, with one row for each unique value in the `row` column, one column for each unique value in the `column` column, and with as many non-zero values as there are rows in `data`.

### Examples

    dat <- data.frame(a = c("row1", "row1", "row2", "row2", "row2"),
                      b = c("col1", "col2", "col1", "col3", "col4"),
                      val = 1:5)

    cast_sparse(dat, a, b)

    cast_sparse(dat, a, b, val)

[Package tidytext version 0.1.2 Index]