DataType

The DataType class represents the data type of a column in a DataFrame. DataType objects are returned by the DataFrame::dtypes() method.

Overview

Polars supports various data types for efficient data storage and operations:

Type	Description
Boolean	True/false values
Int8, Int16, Int32, Int64	Signed integers
UInt8, UInt16, UInt32, UInt64	Unsigned integers
Float32, Float64	Floating point numbers
String	UTF-8 encoded strings
Null	Null/missing values

Constructor

DataType objects are typically not constructed directly. They are returned by DataFrame methods.

Usage

use Polars\DataFrame;

$df = new DataFrame([
    'name' => ['Alice', 'Bob'],
    'age' => [25, 30],
    'score' => [95.5, 87.3],
    'active' => [true, false]
]);

$types = $df->dtypes();
// Returns array of DataType objects for each column

Type Inference

When creating a DataFrame from a PHP array, Polars automatically infers the data type based on the values:

PHP Type	Polars Type
bool	Boolean
int	Int64
float	Float64
string	String
null	Null (or nullable variant)

Example:

$df = new DataFrame([
    'integers' => [1, 2, 3],           // Int64
    'floats' => [1.5, 2.5, 3.5],       // Float64
    'strings' => ['a', 'b', 'c'],      // String
    'booleans' => [true, false, true], // Boolean
    'nullable' => [1, null, 3],        // Int64 (nullable)
]);