cast_sparse {tidytext} | R Documentation |
Create a sparse matrix from row names, column names, and values in a table.
cast_sparse(data, row, column, value)
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 |
Note that cast_sparse ignores groups in a grouped tbl_df.
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
.
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)