flechette

Flechette API Reference

Top-Level Data Types Schema Table Column

Column Class

A data column. A column provides a view over one or more value batches, each corresponding to part of an Arrow record batch. The Column class supports random access to column values by integer index using the at method; however, extracting arrays using toArray may provide more performant means of bulk access and scanning.


# Column.constructor(data[, type])

Create a new column with the given data batches.


# Column.type

The column data type.


# Column.length

The column length (number of rows).


# Column.nullCount

The count of null values in the column.


# Column.data

An array of column data batches.


# Column.at(index)

Return the column value at the given index. The value type is determined by the column data type and extraction options; see the data types documentation for more.

If a column has multiple batches, this method performs binary search over the batch lengths to determine the batch from which to retrieve the value. The search makes lookup less efficient than a standard array access. If making multiple full scans of a column, consider extracting an array via toArray().


# Column.get(index)

Return the column value at the given index. This method is the same as at and is provided for better compatibility with Apache Arrow JS.


# Column.toArray()

Extract column values into a single array instance. The value type is determined by the column data type and extraction options; see the data types documentation for more. When possible, a zero-copy subarray of the input Arrow data is returned. A typed array is used if possible. If a column contains null values, a standard Array is created and populated.


# ColumnSymbol.iterator

Return an iterator over the values in this column. The value type is determined by the column data type and extraction options; see the data types documentation for more.