Headstart¶

Overview¶

The space to headstart with polars

Components¶

Data types and structures¶

The composite elements of polars

flowchart TB
  subgraph structure[Structure]
    direction TB
    dataframe
    series
  end
  subgraph type[Type]
    direction LR
    data_types
    internal_data_types
  end

  dataframe -- included --> series -- contain --> data_types -- implement --> internal_data_types

The core base data structures provided by polars are series and dataframes¹:

A series is a 1-dimensional homogeneous data structure.
A dataframe is a 2-dimensional heterogeneous data structure that contains uniquely named series.

Note

The term "homogeneous" means that all elements in a series have the same data type.

polars provides the following data types, which can be categorized as follows:

Category	Types
Numeric	signed integers, unsigned integers, floating point numbers, and decimals
Nested data types	lists, structs, and arrays
Temporal	dates, datetimes, times, and time deltas
Miscellaneous	strings, binary data, Booleans, categoricals, enums, and objects.

All types support missing values represented by the special value null.

polars utilizes the Arrow Columnar Format for its data orientation for the internals.

For the detail:

Type	Details
Boolean	Boolean type that is bit packed efficiently
Int8, Int16, Int32, Int64	Varying-precision signed integer types
UInt8, UInt16, UInt32, UInt64	Varying-precision unsigned integer types
Float32, Float64	Varying-precision signed floating point numbers
Decimal	Decimal 128-bit type with optional precision and non-negative scale
String	Variable length UTF-8 encoded string data, typically Human-readable
Binary	Stores arbitrary, varying length raw binary data
Date	Represents a calendar date
Time	Represents a time of day
Datetime	Represents a calendar date and time of day
Duration	Represents a time duration
Array	Arrays with a known, fixed shape per series; akin to numpy arrays
List	Homogeneous 1D container with variable length
Object	Wraps arbitrary Python objects
Categorical	Efficient encoding of string data where the categories are inferred at runtime
Enum	Efficient ordered encoding of a set of predetermined string categories
Struct	Composite product type that can store multiple fields
Null	Represents null values

The introduction of polars about data types and structure ↩