arlmet.DataRecord

class arlmet.DataRecord(recordset, position, level, variable, forecast=None, checksum=None, reserved=None)

One ARL data record representing a single 2D variable slice.

Parameters:

• recordset (RecordSet) – Parent record set for the record.

• position (int) – Byte offset of the record on disk, or -1 for a writable in-memory record.

• level (int) – ARL vertical level index.

• variable (str) – Four-character ARL variable name.

• forecast (int, optional) – Forecast hour required when constructing a writable record.

• checksum (int, optional) – Stored ARL checksum from the index record.

• reserved (str, optional) – Reserved one-character metadata from the index record.

ndim

NumPy-style dimensionality, always 2.

Type:

int

recordset

Parent record set.

Type:

RecordSet

position

Byte position of the record in the file.

Type:

int

level

ARL level index.

Type:

int

variable

Variable name for the record.

Type:

str

shape

Grid shape as (ny, nx).

Type:

tuple[int, int]

data

Cached unpacked data, loaded lazily on first access.

Type:

array-like

read(window=None)

Unpack the record from disk, optionally for a subset window.

verify_checksum()

Validate the packed bytes against the stored checksum.

Methods

DataRecord.__init__(recordset, position, ...)	Initializes the array representation.
DataRecord.read([window])	Read and unpack this record eagerly.
DataRecord.to_xarray([squeeze])	Convert this DataRecord to an xarray.DataArray.
DataRecord.verify_checksum()	Verify the packed payload against the checksum stored in metadata.

Attributes

DataRecord.bytes	Get the packed bytes for this data record.
DataRecord.checksum	Get the stored checksum for this data record.
DataRecord.data	Get the data for this record.
DataRecord.diff	Return the attached DIF record when present.
DataRecord.dtype
DataRecord.forecast	Get the forecast hour for this data record.
DataRecord.grid	Get the grid associated with this data record.
DataRecord.header
DataRecord.mode
DataRecord.n_bytes	Get the number of bytes in the packed data record (including the header).
DataRecord.ndim
DataRecord.shape	Return the shape of the data grid.
DataRecord.source	Get the source associated with this data record.
DataRecord.time	Get the time associated with this data record.
DataRecord.vertical_axis	Get the vertical axis associated with this data record.