pub fn iter_unique_dtypes<R: BufRead>(
reader: &mut R,
number_of_rows: Option<NonZeroUsize>,
) -> PolarsResult<impl Iterator<Item = ArrowDataType>>
Expand description
Infers the ArrowDataType
from an NDJSON file, optionally only using number_of_rows
rows.
ยงImplementation
This implementation reads the file line by line and infers the type of each line.
It performs both O(N)
IO and CPU-bounded operations where N
is the number of rows.