Struct TypeMapping 

pub struct TypeMapping {
    pub type_name: String,
    pub field_to_column: HashMap<String, String>,
    pub required_columns: Vec<String>,
}

Maps DataFrame columns to a user-defined type

Specifies which columns are required and how they map to type fields.

Example

// For a SensorReading type:
let mapping = TypeMapping::new("SensorReading".to_string())
    .add_field("temperature", "temp_c")
    .add_field("humidity", "humidity_pct")
    .add_required("temp_c")
    .add_required("humidity_pct");

Fields

type_name: String

Type name (e.g., “SensorReading”, “LogEntry”, “DataPoint”)

field_to_column: HashMap<String, String>

Field name → DataFrame column name mapping Allows renaming: { “temp”: “temperature_celsius” }

required_columns: Vec<String>

List of required DataFrame columns These must exist in the DataFrame for validation to pass

Implementations

impl TypeMapping

pub fn new(type_name: String) -> Self

Create a new type mapping

pub fn add_field(self, field: &str, column: &str) -> Self

Add a field mapping

pub fn add_required(self, column: &str) -> Self

Add a required column

pub fn with_mapping(self, custom: HashMap<String, String>) -> Self

Apply custom column mapping

Extends the existing mapping with custom field→column pairs.

pub fn validate(&self, df: &DataFrame) -> Result<()>

Validate that DataFrame has all required columns

Arguments

• df - DataFrame to validate

Returns

Ok if all required columns exist, error otherwise

Example

let mapping = TypeMapping::ohlcv();
mapping.validate(&dataframe)?;  // Checks for open, high, low, close, volume

pub fn get_column(&self, field: &str) -> Option<&str>

Get column name for a type field

Arguments

• field - Type field name

Returns

DataFrame column name if mapping exists

Trait Implementations

impl Clone for TypeMapping

fn clone(&self) -> TypeMapping

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for TypeMapping

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.