field_mappings_snippet.py

rs = Client(api_server='api.rs2.usw2.rockset.com', api_key='APIKEY')

mappings = [
    rs.FieldMapping.mapping(
        name="twitchTransformation1",
        input_fields=[
            rs.FieldMapping.input_field(
                field_name="price",
                if_missing="SKIP",
                is_drop=True,
                param="price"
            )
        ],
        output_field=rs.FieldMapping.output_field(
            field_name="price", 
            sql_expression="TRY_CAST(REGEXP_REPLACE(:price, '[^\d.]') as float)", 
            on_error="FAIL"
        )
    ),
    rs.FieldMapping.mapping(
        name="twitchTransformation2",
        input_fields=[
            rs.FieldMapping.input_field(
                field_name="latitude",
                if_missing="SKIP",
                is_drop=True,
                param="latitude"
            )
        ],
        output_field=rs.FieldMapping.output_field(
            field_name="latitude", 
            sql_expression="TRY_CAST(:latitude as float)", 
            on_error="FAIL"
        )
    )
]

# create our collection
new_collection = rs.Collection.create("codeDemoFieldMappingsTwitch1", field_mappings=mappings)