DataTypes

class daft.DataType

A Daft DataType defines the type of all the values in an Expression or DataFrame column

classmethod binary() → DataType

Create a Binary DataType: A string of bytes

classmethod bool() → DataType

Create the Boolean DataType: Either True or False

classmethod date() → DataType

Create a Date DataType: A date with a year, month and day

classmethod decimal128(precision: int, scale: int) → DataType

Fixed-precision decimal.

classmethod duration(timeunit: daft.datatype.TimeUnit | str) → DataType

Duration DataType.

classmethod embedding(dtype: DataType, size: int) → DataType

Create an Embedding DataType: embeddings are fixed size arrays, where each element in the array has a numeric dtype and each array has a fixed length of size.

Parameters:

• dtype – DataType of each element in the list (must be numeric)

• size – length of each list

classmethod fixed_size_list(dtype: DataType, size: int) → DataType

Create a FixedSizeList DataType: Fixed-size list, where each element in the list has type dtype and each list has length size.

Parameters:

• dtype – DataType of each element in the list

• size – length of each list

classmethod float32() → DataType

Create a 32-bit float DataType

classmethod float64() → DataType

Create a 64-bit float DataType

classmethod from_arrow_type(arrow_type: DataType) → DataType

Maps a PyArrow DataType to a Daft DataType

classmethod from_numpy_dtype(np_type: np.dtype) → DataType

Maps a Numpy datatype to a Daft DataType

classmethod image(mode: Optional[Union[str, ImageMode]] = None, height: Optional[int] = None, width: Optional[int] = None) → DataType

Create an Image DataType: image arrays contain (height, width, channel) ndarrays of pixel values.

Each image in the array has an ImageMode, which describes the pixel dtype (e.g. uint8) and the number of image channels/bands and their logical interpretation (e.g. RGB).

If the height, width, and mode are the same for all images in the array, specifying them when constructing this type is advised, since that will allow Daft to create a more optimized physical representation of the image array.

If the height, width, or mode may vary across images in the array, leaving these fields unspecified when creating this type will cause Daft to respresent this image array as a heterogeneous collection of images, where each image can have a different mode, height, and width. This is much more flexible, but will result in a less compact representation and may be make some operations less efficient.

Parameters:

• mode – The mode of the image. By default, this is inferred from the underlying data. If height and width are specified, the mode must also be specified.

• height – The height of the image. By default, this is inferred from the underlying data. Must be specified if the width is specified.

• width – The width of the image. By default, this is inferred from the underlying data. Must be specified if the width is specified.

classmethod int16() → DataType

Create an 16-bit integer DataType

classmethod int32() → DataType

Create an 32-bit integer DataType

classmethod int64() → DataType

Create an 64-bit integer DataType

classmethod int8() → DataType

Create an 8-bit integer DataType

classmethod list(dtype: DataType) → DataType

Create a List DataType: Variable-length list, where each element in the list has type dtype

Parameters:

dtype – DataType of each element in the list

classmethod map(key_type: DataType, value_type: DataType) → DataType

Create a Map DataType: A map is a nested type of key-value pairs that is implemented as a list of structs with two fields, key and value. :param key_type: DataType of the keys in the map :param value_type: DataType of the values in the map

classmethod null() → DataType

Creates the Null DataType: Always the Null value

classmethod python() → DataType

Create a Python DataType: a type which refers to an arbitrary Python object

classmethod string() → DataType

Create a String DataType: A string of UTF8 characters

classmethod struct(fields: dict[str, daft.datatype.DataType]) → DataType

Create a Struct DataType: a nested type which has names mapped to child types

Parameters:

fields – Nested fields of the Struct

classmethod tensor(dtype: DataType, shape: Optional[tuple[int, ...]] = None) → DataType

Create a tensor DataType: tensor arrays contain n-dimensional arrays of data of the provided dtype as elements, each of the provided shape.

If a shape is given, each ndarray in the column will have this shape.

If shape is not given, the ndarrays in the column can have different shapes. This is much more flexible, but will result in a less compact representation and may be make some operations less efficient.

Parameters:

• dtype – The type of the data contained within the tensor elements.

• shape – The shape of each tensor in the column. This is None by default, which allows the shapes of each tensor element to vary.

classmethod time(timeunit: daft.datatype.TimeUnit | str) → DataType

Time DataType. Supported timeunits are “us”, “ns”.

classmethod timestamp(timeunit: daft.datatype.TimeUnit | str, timezone: Optional[str] = None) → DataType

Timestamp DataType.

classmethod uint16() → DataType

Create an unsigned 16-bit integer DataType

classmethod uint32() → DataType

Create an unsigned 32-bit integer DataType

classmethod uint64() → DataType

Create an unsigned 64-bit integer DataType

classmethod uint8() → DataType

Create an unsigned 8-bit integer DataType

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