Struct RowMap 

pub struct RowMap {
    pub to: Vec<Option<u64>>,
    pub nrow: usize,
}

Where each row of the input lands in the output: to[old] is its new index, None when the row is dropped; nrow is the output’s row count. Rows may land in any order, and an output row may be fed by no input row (it is then empty), but never by two.

Fields

to: Vec<Option<u64>>

nrow: usize

Implementations

impl RowMap

pub fn keeping(keep: &[usize], nrow_full: usize) -> Result<Self>

The map that keeps the rows keep of nrow_full, in keep’s order.

Errors

If keep lists a row past nrow_full, or one row twice.

pub fn by_names( old_names: &[Box<str>], order: &[Box<str>], nrow_full: usize, ) -> Result<Self>

The map that puts the nrow_full rows named old_names in the order of order: output row i is the input row named order[i], empty when no input row has that name; an input row whose name order does not list is dropped. Row r is named old_names[r]: a row past the names has none, so nothing places it, and a name past the rows names no row.

Errors

If order lists a name twice (its second position would stay empty), or two input rows carry one listed name (they would share a position).