A record that contains information about how and what rows are grouped in the dataframe. This can only be used with aggregate.

O(1) Creates an empty dataframe

Build a DataFrame from a list of (name, column) pairs using insertColumn.

Insert a column into a DataFrame. If a column with the same name already exists it is replaced in-place; otherwise the column is appended at the end. Other columns are expanded (padded with nulls) to match the new row count.

O(k) Get column names of the DataFrame in order of insertion.

Checks if the dataframe is empty (has no columns).

Returns True if the dataframe has no columns, False otherwise. Note that a dataframe with columns but no rows is not considered null.

Type-erased column GADT. Pattern-matching on the constructor recovers the representation; nullability is an optional bit-packed Bitmap (Nothing = no nulls, Just bm = bit i set iff row i is valid).

O(n) Convert a list to a column. Automatically picks the best representation of a vector to store the underlying data in.

Examples:

> fromList [(1 :: Int), 2, 3, 4]
[1,2,3,4]

O(n) Convert a vector to a column. Automatically picks the best representation of a vector to store the underlying data in.

Examples:

> import qualified Data.Vector as V
> fromVector (VB.fromList [(1 :: Int), 2, 3, 4])
[1,2,3,4]

O(n) Convert an unboxed vector to a column. This avoids the extra conversion if you already have the data in an unboxed vector.

Examples:

> import qualified Data.Vector.Unboxed as V
> fromUnboxedVector (VB.fromList [(1 :: Int), 2, 3, 4])
[1,2,3,4]

O(n) Create a column of random elements within a range.

Takes a random number generator, a length, and a lower and upper bound for the random values.

Examples:

> import System.Random (mkStdGen)
> mkRandom (mkStdGen 42) 4 0 10
[4,2,6,5]

O(n) Converts a column to a list. Throws an exception if the wrong type is specified.

Examples:

> column = fromList [(1 :: Int), 2, 3, 4]
> toList Int column
[1,2,3,4]
> toList Double column
exception: ...

Type-safe conversion of a column to a vector of element type a (specify via type application); Left TypeMismatchException when the column's type differs.

>>> toVector @Int @VU.Vector column
Right (unboxed vector of Ints)

>>> toVector @Text @VB.Vector column
Right (boxed vector of Text)

Whether the column stores element type a. For nullable columns, also True when a = Maybe b and the column stores b internally.

Checks if a column contains missing values (has a bitmap).

Checks if a column contains numeric values.

Constraint synonym for what we can put into columns.

Wraps a value into an Any type. This helps up represent rows as heterogenous lists.

Unwraps a value from an Any type. A Null cell yields Nothing.

Given a row gets the value associated with a field.

Examples

>>> map (rowValue (F.col @Int "age")) (toRowList df)
[25,30, ...]

Convert the whole dataframe to a list of rows, one per row index in natural order; each row lists all columns ordered by column index. Materializes every row, so prefer toRowVector for large frames.

>>> toRowList df
[[("name", "Alice"), ("age", 25), ...], [("name", "Bob"), ("age", 30), ...], ...]

Convert the dataframe to a vector of rows containing only the named columns, in the given order. An empty name list yields one empty row per dataframe row.

>>> toRowVector ["name", "age"] df
Vector of rows with only name and age fields

Render an expression as readable, width-aware pseudo-code at the default width (defaultWidth). See prettyPrintWidth to control wrapping.

Render an expression as readable, width-aware pseudo-code: long binary chains wrap onto aligned continuation lines, ifthenelse break onto their own lines (nested else if form a flat ladder), and sub-exprs are parenthesized by precedence.

Configures how a DataFrame is rendered as text: maxRows caps rendered rows, maxColumns collapses middle columns past the limit into an ellipsis, and maxCellWidth truncates long cells. A non-positive field means "no limit".

Sensible defaults for GHCi: 20 rows, 10 columns, 30 characters per cell.

Convert a DataFrame to a CSV (comma-separated) text.

Convert a DataFrame to a CSV (comma-separated) string.

Convert a DataFrame to a text representation with a custom separator.

For showing the dataframe as markdown in notebooks.

For showing the dataframe as a string markdown in notebooks.